It’s a big week in the legislative life of this nascent Congress, which is hustling not only to complete its sequester-conscribed plan for keeping the government operating for the next six months, but also to usher separate partisan budgets through the House and Senate.

But this week portends even more significance in the political life of the Capitol, and not because lawmakers will learn Tuesday night whether Mark Sanford is still on course to hike his way back to the House. The real reason isn’t anything soap-operatic like that. In fact, it’s one-word simple: money.

Because they’re about to leave town for two weeks, these are the final days for House members and senators to raise donations from Washington lobbyists, trade associations and advocacy groups before March 31, the first important date on the midterm elections calendar. Candidates have to tell the Federal Election Commission in April about every dollar they raised and spent in the first three months of this year. The reports will get extraordinary scrutiny for signs of an incumbent’s unexpected fundraising weakness — or else apparent disinterest in running again.

Members already on tenuous electoral footing can ill-afford, quite literally, to post small first-quarter numbers. If they do, their opponents will be on them like jackals. An incumbent’s underperforming FEC report is often an even better documentary tool than a voting record scorecard for reeling in a topflight primary or general election challenger. Warding off such opponents early is at the heart of every incumbent protection strategy.

And so the members committed to running in the midterms have been hunting for dollars at demon speed in recent weeks. A new study of how House members spend their time, released last week by the Congressional Management Foundation, found that more than one-sixth of their day was devoted to political or campaign work, including fundraising. Combined with the hours devoted to media relations, the numbers grew to 26 percent of time spent on self-promotion when in Washington and 32 percent allocated that way in their districts.

That survey was taken in fall 2011, right between elections, and was based on only 25 members comfortable enough with their own priorities to volunteer the details. At times like this on the electoral calendar, the typical number of hours spent raising money is surely higher for many of them.

There’s hardly a way for it to be otherwise, given that the average House member raised $1.6 million for the most recent campaign — or $2,200 every 24 hours from Election Day 2010 until Election Day 2012. For the 25 senators who sought re-election last year, the figures are even more staggering: an average of $11.8 million taken in, or an “in cycle” pace approaching $16,000 a day. And of course, none of these numbers includes what was raised and spent by partisan committees, super PACs and other outside groups.

The current member fundraising surge crests with this week’s cavalcade of cash, with a special focus on the close-call freshmen from both parties and the 30 or so House members and senators representing constituencies that supported the opposing party’s presidential nominee last year.

The biggest event is Wednesday night, when hundreds of big-money benefactors will assemble at the National Building Museum for the National Republican Congressional Committee’s annual March dinner. It’s the largest single congressional fundraising event on the annual calendar, and organizers are hoping to top last year’s record $12 million haul.

Such a deposit would give the NRCC the lead, if only briefly, in its month-by-month contest for the most cash on hand against the Democratic Congressional Campaign Committee. As of the last report, the Democratic group was ahead, $7.6 million to $4.4 million.

The money race will resume soon enough: President Barack Obama is headed to San Francisco in two weeks to raise several million dollars for the DCCC, the first of 14 House and Senate campaign committee fundraisers that he’s promised to headline across the country this year alone.

Last year marked the first $2 billion congressional campaign. There’s no reason to think the 2014 midterms will cost any less.