The Senate is nearing a showdown vote over a Democratic plan to prevent federal student loan interest rates from doubling for 7.4 million students.
Republicans say they back the idea of preventing interest rates on subsidized Stafford loans from rising to 6.8 percent in July.
But they oppose Democrats' way of paying for it, which is raising payroll taxes on high-earning owners of some privately owned corporations.
Republicans want a vote on their alternative. It would raise the $6 billion needed by terminating a health fund created by President Barack Obama's health care overhaul.
Each side lacks the votes to push its bill through the Senate Tuesday.
Both measures, designed with Election Day in mind, would make the other side cast an embarrassing vote against preventing the interest rate increase.