When Paul Clement stands in front of the Supreme Court’s nine justices to argue a case, the effect is akin to watching a game of speed chess, only speed chess contested on nine different boards against nine relentless players. Clement addresses all the boards at once. He’ll make a rhetorical move on one justice here, only to find another skeptical justice requiring attention over there — he has arguments tailored for the court’s fence-sitters especially.

If the justices have anything in common during an oral argument at the court, it is a willingness to express in-your-face sarcasm for a lawyer’s weak gambit. But when Clement, a Republican and former U.S. solicitor general, is on his game, he is a grandmaster, conservative and liberal lawyers agree.

“You want him; he is the best advocate of his generation,” says an old boss, another former solicitor general and Democratic nemesis, Kenneth W. Starr.

It is why, when 26 states decided to challenge the health-care law passed by Congress and championed by President Obama, which mandates coverage for all Americans, they hired Clement, who frequently bills at about $1,000 an hour but is handling the case for a capped fee of $250,000.

The personal stakes in the battle are high for Clement, 45. He has been a longtime favorite of conservative leaders, frequently mentioned by Republicans as being on the short list of Supreme Court nominees should the GOP win back the White House. Such talk has steadily grown since 2005, when President George W. Bush tapped him, at 38, as the nation’s solicitor general, an office that has been a gateway to the Supreme Court in recent years.

Paul D. Clement will present an oral argument before the Supreme Court on behalf of 26 states seeking to have the federal health care law declared unconstitutional. (Nikki Kahn/THE WASHINGTON POST)

Legal allies and foes alike talk with awe about Clement’s professional style. So immersed is he in his cases — their arcane facts, their constitutional precedents, the logical hoops he’d like the justices to join him in jumping through — that he argues without notes. He disdains speechifying.

“Presidential debate-mode doesn’t work,” he says.

At a lectern, his conversational tone is amiably alto, deferential, Midwestern earnest; friends think it befits his suburban Milwaukee background.

“He’s a straight-shooter and honorable,” says Neal Katyal, a former principal deputy solicitor general in the Obama administration, against whom Clement has argued. “Paul’s very likable.”

Now and then, during oral arguments, Clement sports a grin in the midst of making a move or absorbing a momentary battering from the justices. His congeniality doesn’t so much mask his fierce intensity as abet it. His whole mien indicates that these are happy days; that there is nowhere else he’d rather be than with this pack of robed contrarians. It is like watching Bobby Fischer channeling Richie Cunningham from “Happy Days.”

* * *

The grin belies his frequent jitters there. In 2004, as Clement approached the lectern in the Supreme Court to argue a case, his left hand trembled. Sitting inches away, Randy Barnett, nervous, too, as he prepared to argue the other side, studied the quivering hand with fascination. If Clement was tense, the condition must be the natural state of being here, thought a relieved Barnett.

“It happens,” Clement says. He argued his first case before the court in 2001 – “my nervousness was an 11 [on a scale of 10]; it couldn’t have gotten worse.”

Since the start of this millennium, Clement has argued more cases before the Supreme Court than any other lawyer, but some things don’t change, even after 57 appearances. He associates his tension with an exquisite agony, with a steely competitiveness and an adrenaline-fused sharpness not unlike that which girds many athletes. In the end, the tension helps him see a path to a W, the sports term he sometimes uses to describe a legal win.

“If the day ever comes when I don’t feel that nervousness, I guess that will be the time to get out and do something else,” he says.

It is difficult to imagine what that would be. Few people have ever appeared so destined for doing what they do. The Wisconsin schoolboy who demonstrated an early prowess for debating went on to excel at Georgetown University and Harvard Law School, where he served on the law review while Obama was its president and later became the review’s Supreme Court editor. Later, Clement clerked for Supreme Court Justice Antonin Scalia, with whom he probed and argued the points of cases.

“It was a good match . . .” Clement remembers. “It could be pretty intimidating then to get in legal discussions with him. . . . I thought to myself later that after you’ve had those kinds of exchanges with Justice Scalia . . . everything else that follows is a lot less intimidating.”

He went to work for Starr at the prestigious Washington firm of Kirkland and Ellis. “The way I looked at it is that we’d won the Paul Clement sweepstakes when we got him,” Starr remembers. “He had a sterling intellect.”

But the likelihood of a partner’s salary at Kirkland one day couldn’t hold Clement. Eager to get into government work, he took a job as a staff counsel at the Senate Judiciary Committee under the socially conservative Sen. John D. Ashcroft (R-Mo.), who became attorney general for Bush. Clement had worked on a friend-of-the-court brief in Bush v. Gore , the Supreme Court case that decided the 2000 election. Soon after, Clement found himself serving as the chief deputy to Theodore Olson, Bush’s first solicitor general.

Clement’s career since has been a steady ascent to this point where he is generally regarded as the top conservative appellate advocate in the country. In the health-care case, legal analysts on both sides of the debate see Clement’s task as daunting.

“It’s always an uphill case to have the Supreme Court strike down an important act of Congress,” Olson says. “There is a perception that when Congress expresses judgment on an economic matter it is entitled to great deference. Paul will have a significant measure of persuasion ahead of him, a real challenge.”

To Clement, the fundamental question about the Patient Protection and Affordable Care Act is elegantly simple: In compelling citizens to possess or purchase a product — health insurance — has Congress exceeded the powers granted to it under the Constitution’s commerce clause, which gives the federal government broad powers to regulate interstate commerce?

“It’s unprecedented,” Clement says, adding that if the law is permitted to stand, the government could conceivably do anything in the name of regulating commerce under the clause, including, say, making citizens buy American cars to bolster the auto industry. “The government has failed to define a limiting principle to its power here,” he says.

As Clement explains it, the law’s mandate of personal health insurance on individuals is tantamount to forcing people to engage in commerce so that the federal government can, in turn, regulate commerce in which the people have engaged. He smiles to suggest the absurdity of the tautology.

* * *

Clement projects Mister Everyman most of the time. Dark suits are for court. He prefers working in khakis, loafers and a loose-fitting sports shirt.

When he has the time, he bicycles the 35 minutes from his Alexandria home to his small, cluttered office at the Bancroft PLLC law firm on M Street NW. His bike helmet, festooned with the logo of his beloved Green Bay Packers, speaks of Clement’s other great passion. Along with his wife, Alexandra, a Harvard Business School graduate who stays at home to take care of their children, he often dresses his three sons — ages 13, 11 and 9 — in Packers jerseys for holiday cards.

Clement is a self-described “law geek” who teaches as an adjunct professor at Georgetown Law School and spends at least 100 hours preparing for an oral argument before the court.

“By the time he’s ready for a case, he can tell you all about the tributaries to a river somewhere,” says law firm partner Viet Dinh, an old friend dating back to Harvard Law School and an assistant attorney general in the Bush administration. “He doesn’t take his credentials with the court for granted. . . . There’s a reason why, at a podium, he doesn’t need anything in front of him.”

Freed from having to glance down at notes, Clement makes relentless eye contact with the justices, absorbing their voices and expressions.

“So much of oral argument is listening,” he says. “You want to know what troubles them about your case, so you can respond. You have to be engaged; it helps to relax.”

Rivals regard his style with envy.

“He is so comfortable up at the podium — more than me,” says Katyal, who argued the health-care case against Clement at the U.S. Court of Appeals for the 11th Circuit and lost. “The style Paul has can’t really be taught; that’s the art of it. . . . He just has it. He just talks to them.”

What Clement does best, most Supreme Court observers agree, is nimbly, often lightheartedly, weave in his points amid the toughest questions from the justices, casually moving from defense to offense.

“He is catlike when he does it . . . but he does it in such a pleasant, professional way that the court has respect for it — he doesn’t make the mistake of ever overarguing a point,” says Starr who, after teaming with Clement on a First Amendment religious expression case in the U.S. Court of Appeals for the 5th Circuit last year, departed the courtroom believing that his old hire had outshone him.

If necessary during a case, he will duel with justices, all the while keeping his tone light. During arguments in a 2003 age discrimination case, when a sarcastic Scalia expressed skepticism about Clement’s contention that the intent of a statute could be gleaned from a single Senate floor discussion between two of the bill’s architects, the former mentor and clerk had a spirited exchange.

“Who heard that colloquy?” Scalia demanded. “I mean, were they the only two people on the floor? I’m really supposed to get —”

Clement cut in. He told Scalia that “the same number of people heard that colloquy as heard the colloquy that this court relied on” in another age-discrimination case.

Scalia momentarily fell silent.

Recalling the moment, Clement’s voice becomes unusually firm. For a flash, the steely competitor appears.

“You don’t disarm just because of one justice,” he says.

* * *

Clement doesn’t always win. In January, the Supreme Court unanimously ruled against one of his clients, an offshore oil exploration and drilling company. Clement had argued that the widow of a company employee, who generally had worked on an offshore platform but who died in an accident at an onshore facility, was not entitled to benefits under a federal statute which, Clement contended, limited the benefits to those working exclusively offshore.

Indeed, he often represents unpopular positions. In late February, he argued before the court on behalf of the city of Indianapolis, which had been sued for declining to refund the taxes paid in full by some residents for a sewer project while forgiving the tax obligations of others paying on an installment plan.

His frequent supporters on the court temporarily turned into frowning adversaries. Chief Justice John G. Roberts Jr. and Scalia joined Justices Samuel A. Alito Jr. and Anthony M. Kennedy in peppering Clement with questions seemingly suggesting that, in making some residents pay more than others, Indianapolis had violated the Constitution’s equal-protection clause. The court has yet to issue a ruling in the case, but Clement’s exchanges with the bloc of conservative justices warned of possible disappointment ahead. After he predicted that any doubters would be looking “in vain” for proof that Indianapolis was obligated to collect the same taxes from everyone, Roberts cut in. “You said I would search in vain,” the chief justice chided, asserting that he had found just such a point.

But Clement triumphs far more than he falls short, as when the court recently handed down a 9-0 decision in favor of a Montana power company that successfully fought off an attempt by the state of Montana to charge for the company’s use of Montana rivers.

He casually acknowledges that he is good at sensing the justices’ inclinations. Yet in the health-care case, “It’s going to be harder to read people . . . because it is so unprecedented.”

He waves a hand back and forth to suggest all the wild cards out there. “You just don’t know how [Scalia] or some other people will react in a case like this,” he says.

* * *

Since leaving the solicitor general’s office, Clement has been best known for cases of a notably conservative bent. Two months ago, he argued before the Supreme Court against the constitutionality of a Texas redistricting plan crafted by a federal district court and opposed by Republicans, with the court sending the plan back to the district court to be reworked. Next month he will argue on behalf of Arizona’s new immigration law, which the Obama administration will seek to strike down as an unconstitutional infringement on federal power.

Representing House Republicans, Clement is leading the effort to affirm the constitutionality of the Defense of Marriage Act, which prohibits federal recognition of same-sex marriages. He took the DOMA case while serving as a partner at the high-powered firm King & Spalding, which, in 2011, withdrew from the case. Clement promptly resigned from the firm and joined Bancroft, which Dinh had founded.

As Clement came under fire from liberal activists for his DOMA representation, a pack of Democratic and liberal lawyers rose to his defense. Katyal and Attorney General Eric H. Holder Jr. stressed that Clement was simply fulfilling a lawyer’s responsibility not to abandon a controversial client.

Clement has offered no opinion about the political merits of DOMA. Such questions are irrelevant to his role as an appellate advocate, he says, adding that the DOMA statute has met all constitutional tests and that this is reason enough for defending it.

It is his posture toward every major issue he argues, including the health-care law. Friends and relatives have occasionally told him stories about their own struggles with the health-care system, some indicating that they didn’t share his view of the new law.

Asked whether such discussions have ever affected his perspective on the case, he says, “No . . . The reality is it really is a case about constitutional law and what the federal government can do. It doesn’t have that much to do with the underlying issue.”

He pauses. “I don’t mean to say that to trivialize it,” he says. “Obviously, you run into people who run into very difficult situations with respect to getting the health care they need.”

“On a human level, you say to them, ‘I totally understand where you’re coming from,’ ” he explains. “But, on the other hand, you also have to understand that, you know, it’s also really important to have this adversarial system of justice. . . . [If] you take a snapshot of my legal position in this particular case or that case and associate it with the policy issue, well, you know, depending on the case, you’re going to think, ‘Wow, you’re really a crazy conservative’ or ‘You’re a crazy liberal.’ ”

It seems likely that one day the focus will turn on Clement himself. Some legal observers believe that Clement’s hot-button cases jeopardize his chances for a seat on the Supreme Court.

Bruce Ackerman, a Yale Law School professor, sees parallels between Clement and an able but controversial jurist from the ’80s whom the Senate spurned in a confirmation vote.

“Clement is a very well-qualified person, but so was Robert Bork,” Ackerman says, referring to Ronald Reagan’s rejected choice for the high court. Clement “is a person with a high profile that has been heightened by his role in all these cases. Imagine if the decision in the health care case is a 5-4, either way. So Mr. Clement would be at the forefront of a decision that, either way, emphasizes the supreme importance of the next Supreme Court appointment; that dramatizes how one vote would make the difference. . . . It is very much like the Bork matter.”

Is Clement at all concerned about how his association with the health-care case, the DOMA fight and other controversies might affect his future?

“Not really . . .” he says. “I suppose one could try to stay out of the fray and try to take the most innocuous set of cases possible. But boy, that would be boring.”

Clement’s admirers resent the idea that his activism could prove to be a barrier. “It’d be terrible if only the people who didn’t take great chances could get confirmed,” Olsen says.

Looking ahead to his oral argument on the health-care law March 26 to 28, Clement isn’t sure whether he’ll prevail. But he does see a path to a W.

“I think it’s almost impossible for me to argue a case where I don’t see a path to victory. . . .” he explains. “And maybe it’s not, you know, an obvious path – maybe everything has gotta break your way.” Thinking of the justices, he adds: “And maybe they have to come with you on a tough opening premise.”

He smiles, excited enough by the picture in his head to try explaining the sheer frisson of what it is he does.

“But once they do come,” he says, “you have them . . . You just kind of feel like you need that path to victory. Otherwise, it’s sort of, what are you doing up there? You’re not up there just hoping you get lucky.”