WASHINGTON — a nearly 3-2 margin, the Senate voted Tuesday to let lawmakers keep sprinkling bills with home-state pet projects like roads, bridges, water treatment plants, grants to local police departments and special interest tax breaks. But with anti-earmark GOP reinforcements arriving in January, the curtain may soon come down on the practice.

Most Democrats and a handful of Republicans joined in a 56-39 majority to reject a ban on funding for home-state projects not included in the budget proposal that the president submits to Congress each year.

Sen. Olympia Snowe of Maine voted in favor of the ban, while Sen. Susan Collins of Maine, voted against it. Both are Republicans.

Earmark critics, nonetheless, rejoiced in the vote, noting their side had increased by 10 senators since they lost a 68-29 vote on the same question earlier this year. Any votes next year should be closer because a band of anti-earmark Republicans will join the Senate in January. Earmark opponent Jim DeMint, R-S.C., predicted his side will have 45 votes next time.

Senate Republicans bowed to tea party activists after the midterm elections and passed a party resolution declaring GOP that senators would give up earmarks. House Republicans who took 63 seats away from Democrats on Nov. 2 to become the majority in January also have given up the practice.

Most Democrats maintain that earmarks are a legitimate way to direct taxpayer money to their constituents. They were joined by eight Republicans in Tuesday’s Senate vote. On the other side of the ledger, seven Democrats voted with GOP critics of the practice.

Sen. Dick Durbin, D-Ill., said Democrats have made the earmarking process far more transparent than it was the last time Republicans controlled Congress. The reforms include requiring lawmakers to document every project they seek and receive.

“I believe I have an important responsibility to the state of Illinois and the people I represent to direct federal dollars into projects critically important for our state and its future,” Durbin said.

Critics say that peppering most spending bills with hundreds or even thousands of earmark projects creates a go-along-get-along mindset that ensures that Washington spending goes unchecked.

President Barack Obama supports a ban as well, but hasn’t fought earmarks in the past two years as Democrats controlling Congress enacted two cycles of appropriations bills studded with them.

Opposition from Senate Republicans leaves Senate Democrats as the only faction of Congress in a position to try to save the practice of earmarking. But their position doesn’t seem very strong, since House Speaker-in-waiting John Boehner, R-Ohio, has vowed that no earmark-laden bills will pass after Republicans take over the House.

Senate Republican Leader Mitch McConnell of Kentucky had long been a strong supporter of earmarks – they were a big issue in his 2008 campaign – but reversed course shortly after the GOP’s big win in the midterm elections.

McConnell’s move headed off an internal party battle over earmarks and came after an election cycle in which prolific earmarkers Robert Bennett, R-Utah, and Lisa Murkowski, R-Alaska, lost bids to win the GOP nod for their re-election. (Murkowski subsequently won a rare bid as a write-in candidate.)

Sen. Tom Coburn, R-Okla., sponsor of Tuesday’s measure, says GOP support will likely increase as old-timers leave the Senate. And GOP moderate Snowe – facing a potential challenge from the right should she seek re-election in 2012 – switched in favor of the ban after supporting earmarks in a vote in March.

“A lot of the earmarkers are leaving,” Coburn said. “And I think people are going to be looking over their shoulders in 2012 a little bit. This isn’t the last time we’re going to have that vote.”