By Kathleen Hunter

You have to squint most days to actually see Harry Reid doing the work he likes best. Other majority leaders have relished the spotlight — working to shape the party agenda from a television studio or a desk in the front row on the Senate floor — but Reid is most in his element when he roams the shadows in the rear of the chamber, homing in on fellow Democrats who are wavering on the question of the moment.

Such was the scene one night back in April, when Reid was in the final throes of trying to ward off unfriendly alterations to President Obama’s first budget and confronted a pair of colleagues in his way. For several minutes he was locked in an intense discussion with Montana’s Max Baucus and Jon Tester , trying to prevent them from crossing party leadership and the president on the estate tax. But, despite Reid’s intensely focused efforts, Baucus and Tester rebuffed him, and the amendment they wanted was adopted.

Reid got his way in the end; the language was dropped from the final budget resolution. Still, that hushed confab clearly illustrated both Reid’s understated style and the challenges he faces in making it work. Many issues with much higher profiles will be close to arriving in the Senate once Congress returns next week from the July Fourth break, health care and climate change most prominent among them. And so the coming months are shaping up as a make-or-break time for Reid’s legacy — his chance to prove that his reputation for wrangling votes is up to the task of advancing the most ambitious parts of his party’s domestic agenda.

“I don’t think there’s been a majority leader in the past generation who has had a bigger challenge in terms of structuring the agenda and keeping his colleagues on board,” said Steven S. Smith, director of the Weidenbaum Center on the Economy, Government and Public Policy at Washington University in St. Louis.

But Reid enters this period with something like the wind at his back. At the start of the year — his third as majority leader, but his first without George W. Bush in the White House — there were questions about whether Reid’s temperament, ideology and political fortunes in Nevada would hamper his chances of succeeding at every majority leader’s dream: working with a president of the same party to achieve shared goals.

Lately, though, those concerns are losing much of their urgency. With Obama very much the public face of the Democratic Party, Reid allows his much more loquacious top lieutenants, Richard J. Durbin of Illinois and Charles E. Schumer of New York, to take more public responsibility for party message delivery and partisan jousting in the Senate while he concentrates on the behind-the-scenes role of wooing colleagues — the job he excelled at in his six years as whip before becoming floor leader. (He was minority leader in 2005-06). And the sort of social issues on which he and Obama might disagree have essentially been pushed off the agenda.

Most important, perhaps, Reid’s once-forbidding prospects for winning a fifth term next year have been trending upward. Although his poll numbers back home remain poor, the situation facing the Nevada Republican Party appears much worse. The recent soap-operatic disclosures about the personal peccadilloes of the state’s top two Republicans, Gov. Jim Gibbons and Sen. John Ensign , have left the party organization in disarray — and without any viable candidate recruited to take on Reid. (The best remaining hope looks to be second-term Rep. Dean Heller , who appears to be disinclined.) In addition, Obama carried the state by 12.5 percentage points last year and commands solid approval ratings there now. And Reid has been able to use his leadership post to raise money with ease; he had $5.1 million in the bank at the end of March.

What all that means is that Reid can selectively tout White House initiatives that play well to the home-state electorate, such as progress on health care, while continuing to distance himself from the more liberal wing of the party on issues such as gun control and abortion.

Riding Herd

Still, there’s little doubt that Reid will have his hands full just keeping his caucus in line — especially given its geographically and ideologically diverse makeup.

Reid says he expects the tactic of gentle persuasion to work best, given the size of his Senate Democratic flock and the political divergences within it. “I don’t dictate how people vote,” he said in an interview this month. “If it’s an important vote, I try to tell them how important it is to the Senate, the country, the president ... But I’m not very good at twisting arms. I try to be more verbal and non-threatening. So there are going to be — I’m sure — a number of opportunities for people who have different opinions not to vote the way that I think they should. But that’s the way it is. I hold no grudges.”

Reid’s approach will almost surely face a significant test on the health care overhaul, the president’s No. 1 priority this year. Even before the first committee markup is finished, there has been plenty of grumbling by centrist and politically vulnerable senators, mainly about a potential 10-year price tag above $1 trillion. Louisiana’s Mary L. Landrieu and Nebraska’s Ben Nelson have signaled early distaste for the so-called public option that the White House and Reid support; North Dakota’s Kent Conrad is floating the possibility of establishing non-governmental health care “cooperatives” as an alternative. And Reid could stir up a lot more unrest, especially with Republicans but also with some Democrats, if he chooses to move the bill this fall using the budget reconciliation process, which would insulate the bill from filibuster in the Senate.