WASHINGTON -- Stalled in their attempts to pass an extension of federal unemployment benefits, Senate Democrats are now placing their hopes in the hands of two Republicans.

Senate Democratic leadership is eyeing Sens. Mark Kirk (R-Ill.) and Dan Coats (R-Ind.) as the most likely yes votes for any plan to restore those benefits -- which lapsed on Dec. 28, 2013 -- and extend them into the future. A leadership aide told The Huffington Post that the office of Senate Majority Leader Harry Reid (D-Nev.) has been in touch with both Kirk and Coats staffers in hopes of finding a mutually agreeable way to pay for the benefits. Democrats are glad that neither senator has stepped away from those discussions.

"They could have walked away a long time ago," said the leadership aide.

Even if the Senate passes an extension, the Republican-controlled House of Representatives is unlikely to play along. House Republicans will either consider their own version of the legislation or, more likely, not consider anything at all.

To at least apply some pressure to act, though, Democrats must first get a bill through the Senate. With 59 lawmakers having voted for cloture on the previous attempt, they need one more member to end debate and proceed to a vote on the bill itself.

The Democratic leadership regards Kirk as more likely than Coats to vote yes. Their hopes of winning over Sen. Rob Portman (R-Ohio) -- once a top target -- have waned, although lawmakers and advocates have not crossed him off the list of potential supporters.

"We're not giving up on Portman and Coats, but they seem to keep moving the ball," said Judy Conti, a lobbyist with the National Employment Law Project, a worker advocacy group pushing for an extension. "Mark Kirk is in a state with one of the highest unemployment rates in the country. It is a blue state, and it seems to me he has a lot to lose by continuing to play games on this issue."

Conti's moving-the-ball remark refers to the fact that Portman and other Republicans rejected a specific Democratic proposal to pay for the costs of unemployment benefits before turning around and using that same pay-for to restore cuts to military pensions.

While Senate Democrats have put their chips on only two potential Republican votes, they are not willing to drop all legislative demands in order to gain that support. The Democratic leadership aide told HuffPost that the party will no longer agree to a mere three-month extension of unemployment insurance unless it is not offset. Such an extension, the aide argued, would provide little help to recipients since benefits would be applied retroactively back to the beginning of the year and at most provide one more month of assistance.

"We would be right back debating this issue," the aide said.

Instead, Democrats are now waiting to hear from Kirk and Coats what type of pay-fors and programmatic reforms they would support as part of a long-term extension. The aide, who declined to detail what has been discussed so far, cautioned that if the pay-for were too stringent, it could drive some progressive Democrats to abandon their support for the bill. Kirk's office declined to comment. The senator has said previously that he could support an extension with a non-gimmicky pay-for, though he has not stated what that pay-for might be.

In past versions of the measure, Democrats have supported an $8 billion reduction of unemployment benefits. The party would be fine with those reductions again but only as part of a long-term deal. Because they are still waiting to hear Kirk's and Coats' legislative proposals, Senate Democrats no longer expect a vote to happen this week.

Roughly 1.3 million Americans were receiving federal unemployment insurance when Congress let the benefits expire in December. Each week since then, another 70,000 workers have reached the end of their state benefits and now receive nothing, instead of switching to federal benefits. State benefits last up to 26 weeks; the average unemployment spell, as of January, ran 35.4 weeks.

Congress has retroactively approved unemployment insurance several times in recent years. Lawmakers let federal benefits lapse for 50 days in 2010. When the Senate finally reauthorized the benefits, workers received lump-sum payments -- but for some, the damage had been done.