Sen. Ted Cruz speaks at a meetign of the Heritage Foundation, at the Hilton Anatole Hotel in Dallas, Texas on Tuesday, Aug. 20, 2013. He was there to discuss the push to remove funding for federal health care law, also called Obamacare. (AP Photo/The Dallas Morning News, Michael Ainsworth) (Michael Ainsworth/AP)

For 30 long seconds on a Saturday early this month, Ted Cruz stood silent and beaming as hundreds of conservative activists showered him with heartfelt applause in a dimly lighted auditorium. Then he started up again.

“And that reaction right there,” he declared, pointing at the crowd with his thumb and forefinger together, “shows how we win this fight. If I were sitting in the Senate cloakroom, the reaction to that statement would be fundamentally different. I don’t know that I’m quick enough to dodge all the things that would be thrown at me.”

Just like that, Cruz summed up his first seven months as a U.S. senator and exposed the conundrum he represents for the Republican Party: a hero to the conservative base and a worry for the establishment.

Cruz, 42, is a full-bore conservative from Texas whose certitude and combativeness in defense of his positions have made him a rock star to the GOP’s far-right-leaning activists. The comment that brought the crowd to it feet was about shredding Obamacare at all costs.

But that certitude and combativeness also have made him one of the most controversial figures in the Senate, a lightning rod for public and private criticism from Democrats and Republicans alike. The question many are left to ponder as Cruz travels the country targeting President Obama’s health-care law is: What can he realistically hope to achieve in a Senate steeped in tradition and hierarchy as an eloquent yet sharply polarizing figure?

Sen. Ted Cruz (R-Tex.) is renouncing his Canadian citizenship. Does this mean he's going to run for president? (The Washington Post)

The question is increasingly important, as Cruz is frequently mentioned as a 2016 presidential contender. This week, he released his birth certificate amid questions from some who doubt whether he is eligible to be president because he was born in Canada. But Cruz makes the point that he was a U.S. citizen at birth (his mother was an American born in Delaware), and he promised Monday to renounce whatever right he has to Canadian citizenship.

The 2016 speculation has also been driven by the amount of time Cruz has been spending in early presidential nominating states such as Iowa, South Carolina and New Hampshire. He has made two trips to Iowa this year and plans to visit again in October. On Friday, he will be in New Hampshire to headline a fundraiser held by the state GOP.

But he cautions that not too much should be read into those travels. “In my view, it is way too soon for anyone to be focused on the 2016 presidential election,” he said. Cruz insists that his focus is “100 percent” on the Senate, but that is proving a trickier play.

Not a ‘social club’

“Extreme,” “wacko bird” and “over the line” are some of the words Cruz’s Senate colleagues have used to describe him publicly. He has shown none of the traditional deference that junior senators often adopt when dealing with their more senior colleagues.

In one encounter, Cruz tangled with Sen. Dianne Feinstein (D-Calif.), a longtime gun-control advocate, during a Judiciary Committee hearing in March. A staunch defender of gun rights, Cruz peppered Feinstein with questions about the Constitution until, in exasperation, she replied: “I’m not a sixth-grader. Senator, I’ve been on this committee for 20 years.” That confrontational approach has not endeared him to many in the Senate, but Cruz said he will not shy away from defending his principles. “I like and respect my colleagues, but the Senate isn’t a social club,” he said.

Allies of Cruz say they respect his forceful opinions. “He brings clarity to every position he has,” said Sen. Charles E. Grassley (R-Iowa).

The issue on which Cruz has been most clear and forceful lately is an effort to defund Obamacare that has gained little traction. He is pushing a plan that Sen. Mike Lee (Utah) circulated in July calling for Republicans to refuse to support any continuing resolution or appropriations bill that would fund the health-care law. The current funding measure runs though Sept. 30, meaning the government will shut down after that if Obama does not get a new bill.

At a town hall meeting sponsored by a conservative group Tuesday night in Dallas, where Cruz was thrice interrupted by hecklers, the senator offered an impassioned defense of the plan, suggesting that Republicans could win a fight against the president if they simply dig in deeper. “If you have an impasse, one side or the other has to blink. How do we win this fight? Don’t blink,” he argued.

The applause-winning line that brought the crowd to its feet in Ames was the simple declaration: “There is no more important regulatory reform that we can do than to repeal every single word of Obamacare.” As Cruz explained how he intends to do it, the crowd gushed.

But in the Senate, many of Cruz’s Republican colleagues are less impressed. Some have cited the practical and political consequences of a government shutdown. Others have noted that even in a shutdown, the health-care law would be funded.

Outside the Senate chamber one afternoon in late July, Cruz was surrounded by a crush of reporters who tossed out question after question about his push to defund Obamacare. Republican senators, including Tom Coburn (Okla.), Richard Burr (N.C.) and John McCain (Ariz.), have sharply criticized the idea. Cruz chalked up the GOP hesitation to fear.

“There are a great many Republicans who are afraid of this fight because they believe the Democrats will blame Republicans and . . . the mainstream media will repeat word for word the argument of the Democrats,” he told reporters.

About 15 feet away stood McCain, encircled by another pack of reporters. He mocked the idea that he is less courageous than Cruz. “I think he’s right. I’m scared, and I surrender,” McCain said sarcastically, as he waved an imaginary white flag.

Cruz acknowledges that he has become a target for some of his colleagues but says he does not intend to engage in that fight.

“I can’t control what other senators choose to do,” he said. “More than a few senators, Democrat and Republican, have made the decision to throw rocks at me and to publicly insult me. I have not reciprocated. I don’t intend to reciprocate.”

The Senate is a place where tradition and seniority still matter and where the ability to forge relationships can mean the difference between success and failure. It is a place where the newest members often keep their heads down until they get their bearings. Cruz, who entered the chamber as a political star, has largely eschewed those conventions, setting him apart from other freshman celebrities who preceded him.

Barack Obama, for example, entered the Senate to great fanfare in 2005, but he kept a notably lower profile, following the example of Hillary Rodham Clinton. Even Sen. Marco Rubio (R-Fla.), to whom Cruz is sometimes compared, didn’t go big early. Sen. Elizabeth Warren (D-Mass.), a hero of liberals in a way that Cruz is to conservatives, has maintained a quiet presence during her first few months on Capitol Hill.

“He doesn’t appear to be hunkering down for a long Senate career, and he certainly isn’t angling for a Senate leadership position,” said Ed Rogers, a longtime Republican strategist. “I think he is more of a loner than Rubio, Warren or even Obama and certainly Hillary.”

Lee, one of Cruz’s closest allies in the Senate, says there is little doubt that Cruz is serious about being a senator. “I don’t think anyone can doubt his sincerity or his commitment or his dedication to the job,” he said.

‘In God’s hands’

Born Rafael Edward Cruz in Calgary, Alberta, in 1970, to a Cuban father and an Irish American mother, Cruz grew up in Houston. He’s fond of telling the story of how his dad came to the United States with just $100 sewn into his underwear, as an example of how people can lift themselves up in the United States. Cruz’s father (also Rafael), a pastor, is fond of telling the story of how his son began reading Milton Friedman in junior high school and memorized the U.S. Constitution as a teenager.

Cruz went on to become a star debater at Princeton and received a law degree from Harvard, where he dabbled in theater, playing Reverend Parris in “The Crucible.” He worked as a domestic policy adviser on George W. Bush’s 2000 presidential campaign and on Bush’s Florida recount team. Later, he was appointed solicitor general of Texas, serving from 2003 to 2008.

Cruz’s 2012 Senate win was as unlikely as any in the country. He started out as a major underdog against Texas Lt. Gov. David Dewhurst, a well-funded Republican with much of the state party establishment behind him.

But Cruz won the support of the anti-tax Club for Growth and the Senate Conservatives Fund, a group started by then-Sen. Jim DeMint (S.C.), now president of the Heritage Foundation. With a fired-up conservative base behind him, Cruz defeated Dewhurst in a GOP runoff. He skated to victory in the general election.

In his short time in the Senate, Cruz has become a dominant voice in his party, and the question following him as he travels the country is how seriously he is considering a presidential run in 2016. Too early, repeats the Cruz camp.

“That’s in God’s hands,” his father said. “We can’t predict the future.”