WASHINGTON » For much of the last decade, Sen. Charles E. Schumer’s job was to bury Republicans, both as one of his party’s most ruthless strategists and as an inexhaustible fundraiser. It was a job he did so effectively that he was asked to do it twice.

But to watch Schumer operate these days, it would seem he has managed to get some Republicans to forget. There are now regular early-morning chats on immigration reform with Marco Rubio in the Senate gym. There was the excursion last week to the Mexican border with John McCain, who after learning that their visit would fall during Passover offered, "I’ll bring the latkes."

Just this week, Schumer spent a good deal of time on the phone with Tom Coburn of Oklahoma, one of the Senate’s most unyielding conservatives, trying to keep the door open to a deal that would expand background checks for all gun sales.

No one in the Senate right now has a legislative portfolio thicker than Schumer’s, and no one’s political fortunes are as closely linked to the outcome of the major public policy fights now consuming Congress.

He is not only a whisperer to Republicans but also an envoy to the White House and a trusted confidant to the majority leader, Harry Reid of Nevada, who having handpicked Schumer to keep Republicans in the minority is now counting on him as his most important bipartisan bridge builder.

"I give him a lot of leeway," Reid said in an interview, noting that he had personally asked Schumer to take a leading role on gun control and immigration legislation. "I don’t know what we’re going to end up with. But he has taken the ball, and he is running with it."

If Congress passes comprehensive legislation on either of these issues, few lawmakers will be able to claim more credit than Schumer. He would add to his resume a significant achievement that could make it easier to attain what colleagues believe is his ultimate goal after Reid steps aside: the majority leader’s post.

But if these efforts fail, few will shoulder more of the blame.

"I’m happy where I am, and in no hurry," he said in a recent interview when asked about his leadership ambitions. "I’m a hard-working, hard-charging fella. And sometimes leaders would be afraid of that. Harry wasn’t. He wanted to harness and utilize my talents."

He is now the No. 3 Senate Democrat, a leadership post he earned after the first of two successful stints as the head of the Democratic Senatorial Campaign Committee. He was known for dipping into his own accounts to distribute millions to fellow Democrats in tough re-election fights, and he still flies around the country to raise money for his colleagues, tapping his reliable sources of campaign money.

Today he stands on stage at news conferences with many of the same Republicans he sought to defeat. During President Barack Obama’s State of the Union address in February, he and McCain arranged themselves side by side with Sens. Kirsten E. Gillibrand, D-N.Y., and Lindsey Graham, R-S.C., their fellow immigration overhaul advocates. They secured seats just a few feet from the rostrum so the president would see them. (As recently as last year, McCain grumbled to Fox News, "I have never seen Senator Schumer address any issue unless it was political.")

Schumer has heaped praise on Rubio as "Daniel in the lion’s den" for supporting immigration changes that make many conservatives wary. He has called McCain "the glue" in the immigration talks and lauded him for "his wisdom, his strength, his courage."

He has affirmed his respect for Coburn, "a person of integrity," in his words.

But not all Republicans take such a welcoming approach to Schumer, chief among them Sen. Mitch McConnell of Kentucky, the Republican leader. McConnell has blamed Schumer for an ad from 2008 — the year he was up for re-election — that hit Republicans for voting for the bank bailout, a position Schumer and most other Senate Democrats took themselves.

Recently Schumer has tried to mend fences. This year when McConnell’s University of Louisville played Syracuse in basketball, Schumer invited his adversary to attend the game with him. Citing a scheduling conflict, McConnell declined. But if Syracuse and Louisville advance to the NCAA finals next week, the ever-persistent Schumer has said, he will ask the Kentuckian to watch with him in Washington.

If his position at the nexus of the major legislative debates of the day rankles some Republicans, it strikes others as natural. Policy, colleagues say, was always his indulgence.

"When an issue would hit, the first guy out there talking about it was Chuck," said Rep. Peter T. King, a Long Island Republican. "The first guy with a piece of legislation was Chuck. And sometimes when something wasn’t even an issue, Chuck was out there talking about it."

With a jammed schedule these days, Schumer, 62, gallops through the halls of the Capitol, bolting from one meeting to the next with his flip phone glued to his ear. It is not an anti-social way of avoiding people, he insists. He simply has no other way to communicate away from the office because his phone is so outdated it lacks email and Internet.

"Usually the first call I get at home in the morning is Schumer," Reid said. "The last call I get at night: Schumer."

He is viewed less and less as the spotlight-stealing pol about whom Bob Dole once quipped that "the most dangerous place in Washington" is between Schumer and a camera. Sen. Edward M. Kennedy would not even acknowledge him by name at first, though they later became good friends. "He’d point to me," Schumer recalled fondly.

These days the president takes his call.

"I used to have to sort of make excuses to see him," Schumer said. Nowadays? "Not so much."

Schumer served as head of the joint congressional committee that oversaw the inauguration in January, an assignment that came with the perk of riding with Obama from the White House to the Capitol before the swearing-in. And during those 15 precious minutes, Schumer gave the president some advice.

If you want your agenda to succeed, come to us, he said. "The Senate ought to be the caldron to start things out," Schumer recalled saying.

The next day his chief of staff asked him which was more fun: the inauguration or his own bar mitzvah?

The inauguration, hands down, he said. Never one to miss an opening for a personal anecdote, he elaborated. His bar mitzvah fell on Nov. 23, 1963, the day after John F. Kennedy was assassinated. But he and his family went ahead with it anyway only to find their synagogue full of mourners — a much larger crowd than a very nervous young Chuck had expected or wanted.

These days, few would accuse Schumer of being so reluctant about taking center stage.