Senate Republicans on Wednesday voted down a measure to prevent tax cuts for the top 1 percent earners, an amendment introduced by Sens. Bernie Sanders and Ron Wyden to extract a price from the GOP as it moves toward tax reform legislation.

The amendment pertained to the Senate budget that Republicans need to pass so they can proceed with a tax bill that can't be filibustered by Democrats. It failed in a 52-46 vote, with Democrat Heidi Heitkamp of North Dakota joining Republicans in voting "no."

Sanders, a Vermont independent who caucuses with Democrats, said "it's not a radical idea to suggest that at a time of massive income and wealth inequality, when the people on top are doing unbelievably well, at a time when the middle class is shrinking, now is not the time to provide hundreds of billion of dollars of tax breaks to the very wealthiest families in this country." Sanders serves as Democrats' ranking member on the Budget Committee.

The amendment would have required that any bill that cut taxes for the top 1 percent of individuals be subject to the Senate's 60-vote threshhold for passage. People earning more than about $466,000 in adjusted gross income are in the top 1 percent, according to IRS data.

Maine Sen. Susan Collins, one of the centrist Republicans who might have been pressured by such a measure, said she opposed the amendment because the 1 percent is too low a cut-off.

"If he had offered it as a millionaire's, billionaire's tax, then he would have had my vote," Collins told reporters.

Wyden, the Oregonian who is the top Democrat on the Finance Committee, said the amendment "does what the president says what he wants to do, which is not give the relief to the people at the top."

The Sanders-Wyden amendment is just one of several that Democrats had planned to force Republicans to take awkward votes on as they try to advance tax legislation.

Passing a budget unlocks the process known as reconciliation that would allow tax legislation to pass with a simple majority in the Senate.