"His eyes, what color are his eyes?" asks Howard Brodie, the artist whose sketches of Washington's powerful punctuate the CBS nightly news.

"Well, they're pretty," says Patty Lynch, a receptionist in the office of Sen. Dennis DeConcini (D-Ariz.). "I'd say they're gray or blue."

"Make them blue, Paul Newman blue," urges Mary Mahoney, a caseworker.

Mildly amused, Brodie stands there holding the manila envelope containing two black-and-white photographs of the Arizona Democrat. Then a door bursts open to admit Margot Myers, deputy press aide to DeConcini.

"I went in and stared at him across his desk and he looked at me like I was crazy," she reports. "I'd say they're hazel."

So, you're both wrong," Brodie flings over his shoulder as he leaves.

Says Mahoney: "We wanted him to be Paul Newman in disguise."

And from Lynch: "I guess I never looked at his eyes."

Dennis DeConcini is no Paul Newman and neither is he your shoot-from-the-lip Arizona cowboy-in-Congress. Arizonans who have watched his political career say Dennis DeConcini is probably the last guy in the world you'd expect to be the most talked about man in Washington.

Yet, while few in Washington were looking, DeConcini climbed into a position of critical influence on the Panama Canal treaties.

It had been a week of calls from Senate colleagues, pro-treaty lobbyists, anti-treaty diehards, and reporters who suddenly saw him as the pivotal senator in the success or failure of the second treaty.

Yesterday, DeConcini said he would be willing to accept a new understanding on the second treaty, reiterating longstanding U.S. policy against intervention in a foreign country's internal affairs. His statement was seen as potential for compromise.

DeConcini's wife Susan says "gentle, kind-hearted, even-tempered Dennis blew his cover" when he stone-walled the White House with his Panama Canal reservation asserting the right of the United States to intervene militarily in Panama to keep the canal open.

Meanwhile, an Arizona citizens' group is moving to recall him, not because the Panamanians may reject the treaties over the DeConcini reservation but because he voted for the treaty in the first place.

And a leader of the recall movement, salesmand Dan Hough of Phoenix, says DeConcini defied 84 percent of Arizona's voters who want no treaties at all.

Hough charges that DeConcini "was bought off by Carter of a stockpile of copper and DeConcini thought he was being coy and buying voters in Arizona." (That's because Arizona has the nation's largest copper reserves and copper mining was at a virtual standstill last fall, leaving 9,000 unemployed in the industry. Carter recently said the government would buy 225,000 tons of copper from Arizona mines.)

Those who know the 40-year-old legislator profess to make no mistake about this: that for a year Dennis DeConcini has been a freshman senator speaking very softly but, since March, carrying a bigger stick than anybody ever dreamed he could. And he has caught on fast to how they play the game in Washington.

Unruffled by the recall movement ("a bit of a fad in Arizona," says an aide), he rather cavalierly told a Phoenix newsman that instead of trying to recall him, "I think they ought to make me Man of the Year for picking off Torrijos."

The other night he was telling a crowd back home about the treaties and how it was to deal with the Washington power structure, namely the president. There were no deals, he said none whatsoever between him and Carter. Straight-arrow stuff all the way.

"I would like you to know however," he continued in his low-key, manner, "that the federal government is building a seasport in Arizona and we will be opening it soon."

As gags go, it wasn't bad for Dennis DeConcini - "Dennis isn't in the Mo Udall league of humor," says Susan.As grist for gossip goes, it may have contributed another example of DeConcini "arrogance" to that endlessly grinding Washington mill.

Growing Up Political

When Republican Paul Fannin retired from his U.S. Senate seat two years ago, it opened the way for a GOP primary fight Arizonans still talk about. Rep. Morris Udall, a Democrat who was busy at the time with his own run for the presidency, says the race between Reps. Sam Steiger and John Conlan was "so disgusting" with its charges and countercharges dragging in anti-Semitism, murdered Phoenix newsman Don Bolles and even the slaughter of a couple of burros, the Democrat DeConcini picked up support from unexpected Republican corners. He ran with it, making the best of his advantage with what Udall called "a flawless" campaign.

DeConcini says there were smear attempts against him as well because "everytime a De COncini gets into politics, somebody dredges up Joe Bonnano."

In 1949 Evo DeConcini, Dennis' father, met Bonnano, a Mafia chieftain known to the Arizonans only as a Wisconsin cheese merchant. Bonnano had "retired" to Tucson, joined the local Catholic Church, the Italian-American club and bought his way into local charities. Three years later when authorities linked him with organized crime and tried to deport him, Bonnano called in his chips, getting Evo DeConcini and other prominent Tucson citizens to agree to-testify as character witnesses.

The FBI still keeps Bannano under constant surveillance, says the senator, who as Pima County attorney from 1976 kept his own watch. "We could never make a case against him, though I tried. The facts just were'nt there."

The DeConcinis, an Italian-American family of three sons and a daughter, are intensely political (Ora, the mother currently is Democratic National Committeewoman from Arizona), intensely loyal. Says Udall, who had DeConcini support in his won presidential bid: "They stayed with Adlai Stevenson and George McGovern when it wasn't popular to do so."

Retired Arizona Supreme Court Justic Evo DeConcini (who served on the bench with Udall's father) is a conservative. "I wouldn't be surprised if a couple of DeConcinis have voted for me on occasion," says Mr. Republican himself, Arizona's Sen. Barry Goldwater.

Dennis DeConcini, a "middle-of-the-roader" by Goldwater definition, says his father raised the childred "in a moderate political atmosphere stressing that there are two sides to almost every issue - unless it's a moral issue."

Susan DeConcini, member of a pioneer Phoenix family big in Republican circles, met her husband at the University of Arizona. Even then "the handwriting definitely was on the wall - he was passing a petition to run for precinct committeeman, just waiting for the moment he turned 21."

The DeConcinis are millionaires, thanks to Evo's foresight of buying up half of Tucson then forgetting he owned it unitl one day when it was all in the path of urban sprawl. But the Washington members of the family are hardly conspicuous consumers.

The senator and his wife jet a lared eye between Washington and Arizona. They play tennis (but on a neighbor's court) in McLean, and send their three children - Denise, 17, Christine, 16, Patrick, 14 - to public schools.

"We laugh at being instant celebrities," says Susan DeConcini, who is doing graduate studies in social work at Catholic University. What she does not laugh at is the notion that her husband might wind up being regarded by some as the man responsible for defeating the treaties.

Then she bristles and her self-described "Irish temper" flashes. "There's no way you can talk about any one person being responsible for a group vote. Dennis is 97th in Senate seniority, you don't take up his amendment first. It was passed by a large margin of senators who didn't have to vote it."

Neither, she says with equal defensiveness, is "gentle, kind-hearted Dennis DeConcini" arrogant.

"The last thing Dennis would want to be is the person who didn't pull people to together but pulled people apart."

But the pressure is on - "I'm getting it from all sides." DeConcini says calmly. And business has never been so good - or so hectic - in Room 4101 of the Dirksen Office Building.

Like the rest of the staff, Robert Maynes, his press secretary, is relishing the spotlight.

"Some people think he's grandstanding, but we certainly didn't plan for this. Once it comes though, you can't hide. What are you going to do if 60 reporters call? Say he's not going to talk?"

"I'm flattered that you should want to talk to me." DeConcini tells a reporter, disarmingly but not uncharacteristically.

At home, Christine tells her father not to worry about the new notoriety.

"As soon as this thing is over," she says, "we'll just fade right back into the woodwork." Panama Safari

What surprises Phoenix Gazette political writer John Kolbe is 'how much suspense Dennis has been able to milk out of this whole treaty thing." He says DeConcini's position today is exactly what it was four months ago when he returned from the Canal Zone, where, at his own expense, he led a safari that included his wife, his mother, his brother David and Kolbe - and after they arrived, added the U.S. ambassador and an AID official to the party.

Panama's strongman, Gen. Omar Torrijos, invited them all out to his villa for lunch one day, solicitously seating Ora DeConcini, Dennis' mother, next to him.

"He fell in love with my mother - wanted to talk to her more than me," says DeConcini. Toorijos' mother died a year or so earlier and he talked about how close they had been. Then, before any of the DeConcinis knew what was happening, Torrijos began to cry.

It was an awkward opener. But in the 2 1/2 hours that followed, theatrics apparently turned to what Kolbe described as "a lot of dancing around the mulberry bush on the whole question of intervention."

Torrijos was "very generous with his time," according to the senator, "very gracious," remembers his wife - but also "very evasive," says Kolbe.

"I was resonably impressed with Dennis because it's very easy in that diplomatic kind of situation to be the obsequious guest and nod and be polite to everything that's said. Dennis was polite, but he also prodded, saying. That's very interesting, General, but I really don't think you answered my question."

DeConcini says Torrijos told him that the United States had an obligation to intervene militarily in case of external threats. As for internal threats . . . well, there matter's got murky.

"I said, "What if there is strike in your country and the canal is closed?" and he said, 'That will never happen.' And I said, 'Well, maybe it doesn't in your form of government, but strikes happen even in governments other than democracies.

"I then asked about an internal revolution and if as part of that revolution, the canal was closed. Do we have the right to intervene? He said only if you come in at my request on our side."

Kolbe says Torrijos told DeConcini that "you should not trust any leader who signs a receipt to allow you to interfere in his country because tomorrow, if I decide to become Omar the First, you would have to defend my dynasty."

Back in Washington, DeConcini talked to the administration and studied the Baker-Byrd amendments.

"I realized that his (Torrijos') interpretation and ours were a little different. That's when I commenced to draft our amendment."

The day before the vote, DeConcini met with Carter and says he told the president he thought there was a different interpretation put on the leadership amendment. "The president disagreed with me. He said, 'No, I don't think so.' And he said he didn't think my amendment was necessary, 'but if you have to have it in order to vote for it, fine.'" 'Dennis Is Tough'

Mo Udall says the White House has been after him to lobby DeConcini. Before the March vote, "Fritz (Mondale) asked me to bring some pressure to bear. I said Dennis is tough."

DeConcini says the first he knew the government was going to buy the copper he had been asking them to stockpile since last Semptember was a week before the first treaty vote. "Up pop some people from the vice president's office. I said, 'Does this have anything to do with the Panama Canal?' and they said absolutely not. They were talking about 225,000 tons [DeConcini wanted 1.3 million] and I said it wasn't going to work - too little too late - but I didn't want to say "forget it."

While he was in Nigeria, the President called Dennis DeConcini. Says DeConcini, "Somebody asked me, 'Don't you think that's a bit too much?' And I said, 'Well, I don't know that I would do that but, my gosh, he has a communications system and a free hour and I can understand he'd like to utilize his time."'

The way DeConcini told it in Arizona, when Carter's call came through, Susan DeConcini told the White House operator the senator was sleeping. Could he call the president back?

Deciding that perhaps Susan DeConcini hadn't understood, the operator repeated that it was the president calling from Nigeria.

"I told you that he's sleeping right now," Susan DeConcini said. "If you recall, the senator called the president back last night and because of a change in time zones was told the President was sleeping. And he didn't ask you to wake him up."

Sitting in the Senate Dinning Room the other day, DeConcini thought about Jimmy Carter.

"It may be that he is too good for the office because he is not a brutal man. Maybe when I vote against this treaty - if I do - I'll find otherwise. But," Deconcini mused, "he doesn't leave you with the idea that he'll do something to you if you dissagree with him."