In June, a similar bill offering a two-year extension of the 3.4 percent rate failed 51-46.

A failed vote would leave the Senate without an answer on student loans for another week. But on Tuesday, some Senate Democrats said they might now be open to a proposal along the lines of a bipartisan Senate plan to peg the interest rate to Treasury's borrowing rates. If that plan is pursued, a likely sticking point will be whether rates should be capped to keep them from rising too high, and where that cap should be set.

That bipartisan bill is similar to one passed by the House, and one proposed by President Obama. Republicans have hammered Democrats for the last several weeks for failing to use these ideas as a basis for advancing a bill in the Senate.

But as of Wednesday, Senate Democrats had not said whether they would allow a vote on the bipartisan loan bill.

In the House, members meet at noon to resume work on the 2014 energy and water spending bill, H.R. 2609. The House worked late into Tuesday night on amendments to this bill, mostly killing off Democratic amendments that would have boosted renewable energy and science programs.

Ten amendments that were debated Tuesday night still need a vote, and other amendment proposals are expected to be debated and voted on today. It's not clear whether the House will finish work on the spending bill today on Thursday.