Washington ? Senate Democrats on Wednesday preserved pet projects sought by a lobbying firm under federal investigation and tried to nail down support for big domestic spending increases in hopes of passing a wrap-up budget bill by week’s end.

Democrats defeated, by a 52-43 vote, an amendment to strip 13 projects that the PMA Group has pressed for. The firm, now disbanded, is accused of illegally using straw donors to funnel campaign cash to lawmakers.

At the same time, Democrats sought a few GOP votes for the $410 billion bill after two Democrats came out against it over the cost and two more threatened to withhold support over changes in U.S. policy toward Cuba.

Democrats and their allies control 58 seats in the Senate, but 60 votes will be needed to close debate and free the measure so President Barack Obama can sign it. Democrats probably will need votes from perhaps five or six Republicans if the measure is to pass tonight or Friday.

Democratic leaders were cautiously optimistic Wednesday night they could do just that. Passage would allow lawmakers in both parties to get the thousands of pet projects they crave and award above-inflation budget increases for education, nutrition programs, transportation and foreign aid.

The spending bill wraps together the budgets for 12 Cabinet departments and other agencies. The measure was written mostly over the course of last year, before projected deficits quadrupled and Obama’s economic recovery bill left many of the same spending accounts swimming in cash.

The White House promises Obama will sign the bill despite unhappiness over the 8,000 or so homestate pet projects.

Democrats Evan Bayh of Indiana and Russ Feingold of Wisconsin said they will vote against the bill; both urged Obama to veto it.

“There’s just a disconnect between what people are having to go through in their daily lives — tightening their belts, economizing where they can — and what they see the government is doing,” Bayh said in an interview. “I just think it’s tone deaf and, substantively, we do need to get the deficit under control.”

Democratic leaders appeared to be holding onto other Democrats, and some GOP leaders acknowledged that the bill is going to pick up GOP votes that would prove critical.

“I just don’t know whether we have enough votes to stop it,” said Sen. John Ensign, R-Nev., the No. 3 GOP leader.

The measure contains budget increases, on average, of 8 percent for the domestic agencies it covers, far more than they received under the Bush administration.

Democratic Sens. Robert Menendez of New Jersey and Bill Nelson of Florida are considering whether to oppose the legislation because it would ease rules on travel to Cuba and make it easier for Cuba to pay for imported food and medicine.

The House passed the bill last week, and Senate Democratic leaders want to follow suit by Friday. That’s when a temporary law that keeps the government in business, mostly at 2008 levels, runs out.

The bill needs to be enacted by midnight on Friday — or a stopgap bill must be passed in its place — to avoid a shutdown of most domestic agencies.