Their calculation is uncomplicated. With only so much money to go around in an election year that is tilting the GOP’s way, Democrats need to concentrate resources on preserving the chamber they have now. Losing the Senate, they know, could doom whatever hopes Barack Obama has of salvaging the final years of his presidency.

The triage idea is taking hold in phone conversations among donors and in strategy sessions between party operatives. Even some of the people who have invested the most to get House Minority Leader Nancy Pelosi back into the speaker’s chair are moving in that direction.

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“There is no question that Democratic donors are shifting towards the Senate in 2014. They will continue to support Nancy, but everyone agrees that the emphasis is going to be on the Senate,” said Joe Cotchett, a prominent San Francisco trial attorney and friend of Pelosi’s who has donated hundreds of thousands of dollars to Democratic Party candidates and causes. “When you see people like [longtime California Democratic Rep.] George Miller announcing that they are not running again, you know where the money will be going.”

“…[U]nless we have a George Washington Bridge fiasco in the House,” he added, referring to the traffic scandal that has engulfed Republican New Jersey Gov. Chris Christie, “control is not going to change.”

It’s a delicate decision for Democrats and one they are not taking lightly. None of them wants to surrender the House to Republicans for another two years, leaving Speaker John Boehner (R-Ohio) and a rowdy band of tea party lawmakers in charge. Ceding ground to Republicans this year would make it that much harder for the party to win back the House in 2016, which could be a more favorable year for Democrats.

But with their party weighted down by an unpopular president and his even more unpopular health care law, many Democrats are worried about the election. And their anxiety is most pronounced about the Senate.

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One handicapper recently characterized the battle for that chamber — Republicans need to net six seats to win control — as a “coin flip.” Making up their 17-seat deficit in the House, on the other hand, looks like a nonstarter for Democrats; it would not be surprising, some pundits say, for Republicans to expand their House majority.

Even Democratic National Committee Chairwoman Debbie Wasserman Schultz hedged Wednesday when asked if her party would take the House, forecasting only that it would gain seats.

“I’m not going to confidently predict that Democrats will take the House back,” she said when asked about the midterm elections during POLITICO’s post-State of the Union event.

So Cotchett and other Democratic bigwigs are adopting a realpolitik approach to giving.

In 2012, Tin House magazine publisher Win McCormack gave $125,000 to CREDO, a liberal super PAC devoted to unseating tea party-aligned House Republicans. But this year, his focus is on keeping Democrats in control of the other chamber.

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“Democratic donors such as myself are likely — I would say certain — to increasingly shift their attention and resources to Senate races,” McCormack wrote in an email.

The shift comes as House Democrats are raking in big money for the midterms, outperforming both Senate Democrats and their House GOP counterparts. Buoyed by the tea party-led government shutdown and an energetic push from Pelosi, the Democratic Congressional Campaign Committee brought in more than $70 million through the end of November, compared with $48 million for the Democratic Senatorial Campaign Committee. Despite being in the minority, the DCCC has outraised the National Republican Congressional Committee by $15 million. And House Majority PAC, a leading Democratic outside group that invests in congressional races, raised $7.5 million in 2013, nearly double the amount it took in during the first year of the 2012 election cycle.

( Also on POLITICO: DWS: Not confidently predicting House takeback)

Some Democratic operatives think a big chunk of that money should be going to Senate contests instead — and they’re beginning to make that case to wealthy contributors. One senior Democratic strategist who is involved in a number of Senate races said conversations with many of the party’s biggest donors about shifting their giving away from the House and toward the Senate had begun and that, “it’s only a matter of time before we start seeing the results.”

“After the health care rollout and with the start of the new year, Democratic donors are starting to focus on a critical choice they have to make: Donate money to pick up a small handful of House races or defend the Senate majority at all costs so that the president can get something — anything — done,” the strategist said.

House Democratic strategists insist they’re not worried about campaign money, regardless of their prospects. Pelosi, they point out, is one of the party’s most formidable fundraisers and will always be able to attract donations. And, after four years of tea party rule in the lower chamber, many liberals are motivated to open their checkbooks.

Some Democrats also say that many donors simply aren’t yet ready to accept the idea that the House is a lost cause.

“People who are sick and tired of this reckless Republican Congress that’s hurting the middle class are investing in the DCCC at a record-breaking pace,” said Jesse Ferguson, the DCCC’s deputy executive director. And Andy Stone, a spokesman for House Majority PAC, said, “Donors are excited by the plethora of Democratic pick-up opportunities across the country.”

Evangeline George, a Pelosi spokeswoman, said: “The House is in play. Leader Pelosi is confident that House Democrats will have more than sufficient resources to compete for the net 17 seats needed to win the majority.”

The DSCC did not respond to a request for comment.

It’s not just donors who are figuring out where to focus their attention. President Barack Obama, who recently reopened his long-dormant office of political affairs in preparation for this year’s midterms, will be deciding how to spend time fundraising and campaigning leading up to November. His assessment of how endangered the Senate appears — and how long the odds of a House takeover are — are bound to factor into those judgments.

A White House spokesman declined to comment for this story.

If Senate Democrats are fretting about dollars, it’s for good reason. So far this election, Republican groups have spent more than $17.2 million on TV commercials in races, slightly less than double the $8.8 million figure that Democrats have invested. In five crucial states — Arkansas, Iowa, Louisiana, Michigan and New Hampshire — Republicans have outspent Democrats by more than 3 to 1. Many of the GOP groups have focused their firepower on battering Democrats over Obamacare.

With Republicans pouring money into contests, some Democratic donors are feeling an increased urgency. Leo Hindery, a New York City media mogul, has argued that donors should zero in on the small number of races that will determine control of the Senate.

“Holding the Senate [is] in some people’s eyes taking precedence over recapturing the House,” Hindery, one of his party’s most prominent contributors, said in an interview.

Not everyone believes that a special emphasis on the Senate is a good idea. Many Democratic donors view winning back the lower chamber as a long-term project.

“The political game isn’t over on Election Day of 2014,” said Steve Mostyn, a prominent Houston attorney who is one of the Democratic Party’s biggest donors. “If Democrats don’t work to protect and pick up House districts this cycle, then they’ll start further behind in 2016, and we have no intention of doing that.”