In one week, Congress will return to Washington and start tackling its enormous to-do list. Senate Majority Leader Harry Reid has already said restoring long-term unemployment benefits that lapsed on Dec. 28 will among the first orders of business for the chamber when it reconvenes — but how likely is passage? And what happens if it fails?

A recruiter, right, meets with a job seeker at the Columbus Career Fair in Columbus, Ohio, U.S., on Thursday, Dec. 5, 2013. Applications for U.S. employment benefits unexpectedly fell last week to the lowest level in more than two months as the data becomes more difficult to adjust for seasonal variations during the year-end holiday period. Photographer: Ty Wright/Bloomberg A recruiter, right, meets with a job seeker at the Columbus Career Fair in Ohio. (Ty Wright/Bloomberg)

Conversations with several people involved in the push present a fairly clear road map, though no doubt a very difficult one. The first order of business, as noted, is getting 60 votes for a bill by Sens. Jack Reed (D-R.I.) and Dean Heller (R-Nev.), which would extend jobless benefits for three months at a cost of $6.5 billion. A confirmation vote for Janet Yellen as Federal Reserve chair may come first, I’m told, but either way Reed-Heller will be dealt with very quickly.

Advocates are hoping that other Republicans have been reading the brutal polls on letting benefits lapse and hearing from constituents on the issue over the holidays, and will return to Washington with a different mindset. “A lot of it is going to be a reflection of what my colleagues are hearing from back home,” Reed told The Post this week.

I wouldn’t rule passage out, but as of today, the bill’s prospects look dim. Heller is the only Republican on board, so four more would be needed in the Senate — and that’s before one even considers the House prospects, where Speaker John Boehner insists that any unemployment extension be paid for with offsetting cuts. The Reed-Heller bill does not have an offset, which my colleague Ryan Cooper notes is a good thing: We shouldn’t be afraid of some paltry deficit spending to help those truly struggling in this economy. Perhaps Boehner will come to see it that way if a bipartisan bill emerges from the Senate and public pressure continues apace. But maybe not.

In that case, what’s next? There are two likely vehicles to get an extension of benefits through. As Greg Sargent reported earlier this month, one idea, spearheaded by Rep. Chris Van Hollen (D-Md.), is to attach an extension to the farm bill. Van Hollen wants House Democrats to say they won’t agree to any farm bill that doesn’t include an extension of long-term unemployment benefits.

Another alternative is the omnibus bills ready to hit the Senate floor in January. The Ryan-Murray budget simply sets funding levels but does not appropriate money — and a big fight over which line items get what money is sure to engulf the Senate in January. It’s possible, I’m told, that an unemployment insurance extension could be worked into this horse-trading.

The latter two options are, of course, the least desirable — it would likely mean trading away further food-stamp cuts in the farm bill in exchange for the extension, or taking money from some other domestic priority during the appropriations process. In short, both would allow Republicans to extract a price for agreeing to the extension, whereas Reed-Heller would not.

But the true danger is that none of the above works. Past January, not only may it be too far along to offer the benefits retroactively — as Reed-Heller does — but there will be pressure to push forward down other avenues that have a better chance of success, like finally getting to comprehensive immigration reform. If we don’t have an extension of long-term jobless benefits one month from today, it’s time to be really worried.