Washington (CNN) -- House Speaker John Boehner's proposal to avert the looming fiscal cliff's automatic tax increases failed to curry enough Republican support Thursday night, after which Congress left for the holiday with no clear end in sight in the high-stakes debate. Boehner said earlier Thursday that he was confident that his so-called Plan B -- which would extend tax cuts that are set to expire at year's end for most people while allowing rates to increase to 1990s levels on income over $1 million -- would pass the House, and in the process put pressure on President Barack Obama and the Democratic-controlled Senate. But his gambit seemed in doubt later as Republican leaders struggled to get most all their members to sign on -- even enlisting senators like Sen. Rob Portman, to work the House floor -- knowing the chamber's Democrats oppose it.
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NEW: "The president will work with Congress to get this done," the White House says
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The House Speaker says his Plan B wasn't voted on because it didn't have "sufficient support"
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A bill to alter cuts did narrowly pass the House; the White House says it would veto
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The fiscal cliff's tax hikes and spending cuts are set to take effect in January
Senior administration officials said Obama and @placeholder have not spoken since Monday, when the president made a counterproposal to a Republican offer over the weekend.