Rep. Chris Van Hollen celebrated a hard-fought victory on his DISCLOSE Act last week, but the Maryland Democrat needs Senate leaders to work some magic if the campaign finance reform bill is to reach the president’s desk in time to influence this year’s elections.

Senate Majority Leader Harry Reid (D-Nev.) and Sen. Charles Schumer (D-N.Y.) last week pledged to work “tirelessly” to move the bill. But getting anything done has become an absolute chore in the Senate, and the stack of bills already languishing at the desk includes extension of unemployment benefits and tax breaks and a host of jobs-related bills.

The campaign finance disclosure bill won’t see any action in the Senate until after the July Fourth recess, according to Democratic aides.

A Senate Republican aide also dismissed Democratic claims that the GOP faces a political cost for defending secret corporate cash in politics. “Why is standing up for free speech ever going to put us in a bad spot? … If the Democrats want to make this a popularity contest, we’re very happy to be standing on the side of the Constitution and free speech.”

Democrats hope that some moderate Republicans will be susceptible to the argument that a vote against the bill is a vote for an unending secret slush fund of corrupting corporate cash.

Democrats’ top target is likely to be Sen. Olympia Snowe (R-Maine), who co-authored key pieces of the landmark McCain-Feingold campaign finance reform bill and criticized the Supreme Court’s Citizens United decision striking down limits on corporate political spending. Other potential Republican targets include Maine Sen. Susan Collins and Massachusetts Sen. Scott Brown.

But Democrats also face losses in their own ranks, with Sens. Frank Lautenberg (N.J.) and Dianne Feinstein (Calif.) ripping the House’s carve-out for the National Rifle Association and a limited number of other large nonprofit advocacy organizations.

Though out of his hands, the bill’s fate in the Senate will weigh on Van Hollen’s standing among his colleagues, many of whom continue to doubt its prospects there. But last week, at least, on his own turf, the Maryland Democrat engineered a stunning turnaround for his signature initiative.

Van Hollen had limped into the previous weekend with support ebbing for the package. At that point, leadership aides counted about 130 Democratic votes for it. In less than a week, Van Hollen — backed by the White House and other top House Democrats — built a winning coalition.

He started the push facing two distinct problems. Members of the Blue Dog Coalition, whom Van Hollen had accommodated by crafting the NRA exemption, were balking at angering business groups aligned in opposition only to see the measure stall in the Senate. Separately, liberal and black lawmakers, enraged by the NRA deal, were pledging to bolt.

Van Hollen spent the weekend working the phones, placing about 50 calls to wobbly Democrats. He talked to White House Chief of Staff Rahm Emanuel, his predecessor helming the Democratic Congressional Campaign Committee, and secured a commitment that the administration would publicly back the package — an important signal to liberals.

And from Schumer, author of that chamber’s companion measure, he sought a declaration from Senate Democratic leadership that they would, in fact, follow through once the House acted.

The White House statement came on Monday, followed by the letter from Senate Democratic leaders on Tuesday. Both helped lay the groundwork for the arguments that leaders made to their rank and file all week.

But Democratic leadership sources said there were no developments that unlocked large blocs of votes. Instead, Van Hollen spent most of the week holed up in his Capitol hideaway, chipping away at holdouts one at a time.

Throughout, the CBC remained the trickiest problem for leaders. The group’s weekly Wednesday meeting became a platform for Members to air simmering frustrations with the bill, and more broadly, at Congressional inaction on a package that included funding for summer jobs programs. Despite appeals from Majority Whip James Clyburn (D-S.C.) and Rep. Sheila Jackson Lee (D-Texas), many in the CBC remained opposed. “We were a little concerned, because not a lot of votes were moved,” one leadership aide said.

The leaders’ pitches to the left and right flanks of the Democratic Caucus converged on Thursday, the day of the vote. At a Caucus huddle that morning, Congressional Progressive Caucus Co-Chairwoman Lynn Woolsey (D-Calif.) told her colleagues that liberals would be looking to see Blue Dog votes for the package that contained their NRA fix before they lined up behind it themselves, according to sources in attendance.

Then Rep. Earl Pomeroy (D-N.D.), a Blue Dog, rose to explain why he was backing it.

And Van Hollen, in what aides described as a passionate final appeal, laid out the political urgency.

To those nervously eyeing opposition from the U.S. Chamber of Commerce, the Maryland Democrat made the case that Republicans are actually assembling tens of millions of dollars in other outside war chests — money that will fund anonymous attacks if the bill languishes.

Democrats headed into the vote at least a half-dozen votes short. But after Blue Dog “yes” votes started piling up on the board, liberals rallied.

Thirty-eight of 58 Blue Dogs ended up supporting the bill, as did 29 of 41 CBC members. It passed 219-206.