WASHINGTON -- Senate Republicans on Tuesday blocked a bill that would have frozen student loan interest rates before they are set to double on July 1.

In a partisan vote of 52 to 45, the Senate failed to reach the 60 votes needed to begin debate on the Democratic bill. Sen. Olympia Snowe (Maine) was the lone Republican to vote "present." A Snowe spokesman told The Huffington Post her vote was related to her practice of voting "present" on legislation that contains the potential or appearance of association with the private business activity of her husband.

The vote wasn't much of a surprise: Republicans have been signaling they would filibuster the bill because of its cost offsets. Democrats would cover the $6 billion cost of keeping student loan interest rates at 3.4 percent for another year by raising Social Security and Medicare payroll taxes on certain high-earners. By contrast, Republicans have called for nixing a preventive health fund to pay for it.

Ultimately, the vote gives Democrats another chance to try to frame Republicans as favoring the wealthy over the middle class in the midst of election-year politicking.

During debate on the bill, Sen. Tom Harkin (D-Iowa) said Republicans were "afraid" to agree to let it come up for debate because they would be forced to choose between helping college students and protecting the rich.

"Some of my friends on the other side of the aisle maybe will think that students are more important than a few wealthy people in this country not paying their fair share of taxes" if the bill were allowed to come up for debate, Harkin said. "That's what this vote is ... Republicans don't even want to proceed to go there."

The ultimate goal of the GOP, he said, is "to kill the preventive health fund."

But Sen. Lamar Alexander (R-Tenn.) said Democrats have no room to talk when it comes to draining the health fund to pay for other things, since many of them, along with President Barack Obama, agreed to pull $5 billion from the fund in February to pay for a payroll tax cut extension.

"Let's be clear about this. It's not just Republicans who think that fund isn't the best use of taxpayer's money," Alexander said. "So it's a bipartisan proposal."

In a show of just how much politics is driving the debate, Alexander repeatedly said that GOP presidential candidate Mitt Romney supports keeping the interest rate on student loans at 3.4 percent.

"We agree with President Obama, we agree with Gov. Romney, we agree with the House of Representatives that it should stay at 3.4 percent," he said. "The only difference is how we pay for it. They want to raise taxes on people who are creating jobs, while we're still in the midst of the greatest recession since the Great Depression."

Harkin tried to defend Obama's past decision to pull money from the preventive health fund as a one-time deal. But he said he didn't support the idea then and still doesn't.

"I was not very supportive of that," he said. "I thought we should have taken the money from elsewhere."

Democrats must now decide whether their next push on a student loan bill will be tied to taxing the wealthy or paid for in a way that Republicans will swallow.

UPDATE: 2:36 p.m. -- White House Press Secretary Jay Carney called it "extremely disappointing" that Republicans blocked the bill.

"We're pleased that despite failing to address it in their budget, Republicans in Congress now profess to be concerned about this coming rate hike," Carney said in a statement. "But now it’s time for them to stop refighting old political battles and prove they’re serious by proposing a real solution to keep rates low for students without burdening middle class families or undercutting preventive health care for women."