Washington ( CNN ) -- The U.S. Senate on Wednesday passed a Democratic plan to extend the Bush-era tax cuts for middle income Americans while rejecting a Republican alternative to continue all of the cuts -- twin votes that help to crystallize the position of the two parties on a critical issue heading into the fall campaign . The Democratic proposal passed in a sharply polarized 51-48 vote , while the Republican plan was defeated 45-54 . Vice President Joe Biden , the constitutional presiding officer of the Senate , was on hand to cast a tie-breaking vote if necessary . Strategists on both sides of the aisle acknowledge that neither plan has a chance of passing both the Democratic-controlled Senate and the Republican-controlled House of Representatives . GOP leaders in the House have indicated they have no intention of bringing the Democrats ' plan to a vote . House Speaker John Boehner , R-Ohio , pledged in a written statement after the votes to `` stop the tax hike , '' and insisted Republicans are the only ones addressing the `` threat to our economy . '' Republican National Committee Chairman Reince Priebus blasted Democrats for backing a `` disastrous plan to raise taxes on small businesses and job creators '' while putting `` their tax-and-spend agenda ahead of creating jobs . '' President Barack Obama , however , said , `` House Republicans are now the only people left in Washington holding hostage the middle-class tax cuts for 98 % of Americans . '' The U.S. economy `` is n't built from the top down , it 's built from a strong and growing middle class , and that 's who we should be fighting for , '' he declared . Rival Bush tax plans . Wednesday 's votes were primarily about political positioning in the heat of the 2012 election season , as well each party 's opening bid in what is sure to be a frenzied legislative negotiating session this autumn . The economy is approaching a so-called `` fiscal cliff '' brought on by the looming expiration of several tax cuts as well as the approach of a series of mandatory spending cuts . `` At the end of the day this ( legislative maneuvering ) is n't going to solve the problem . It 's going to be political posturing all the way up to the November election , '' said Sen. Bill Nelson , D-Florida . The Democratic bill approved by the Senate on Wednesday would extend the Bush tax cuts -- now set to expire at the end of the year -- just on incomes under $ 250,000 for a couple and $ 200,000 for an individual . The GOP bill would extend the tax cuts for all taxpayers -- including the wealthiest Americans -- and includes a requirement that Congress tackle comprehensive tax reform within a year . Republicans argue that any tax hikes could derail what is already considered a weak recovery . Opinion : Taxmageddon is headed our way . After Senate leaders jockeyed for days over procedural issues tied to consideration of the bills , Senate Minority Leader Mitch McConnell , R-Kentucky , unexpectedly announced Wednesday morning that Republicans would agree to Democratic demands and hold back-to-back votes requiring neither side to garner a filibuster-proof 60-vote margin . McConnell 's decision gave the Democrats bragging rights , allowing them to tout the fact that their bill is capable of passing the Senate . But it also gave Republicans the ability to put several centrist Democratic senators on the spot , forcing those Democrats to vote for a politically contentious plan that raises taxes on certain Americans . `` We owe it to the American people to let them know whether we actually think it is a good idea to double down on the failed economic policies of the past few years or whether we support a new approach , '' McConnell said before the vote . `` By setting these votes at a 50-vote threshold , nobody on the other side can hide behind a procedural vote while leaving their views on the actual bill itself a mystery . '' For their part , Democrats point to polling that shows a majority of Americans support their approach . `` Our bill has the support of President Obama , has the support of the Democratic caucus and has the support of the American people . A majority of Americans , including a significant majority of Republicans , agree taxes should remain low for the middle class and the top 2 % should pay their fair share to reduce the deficit , '' said Senate Majority Leader Harry Reid , D-Nevada . `` The only place there is no agreement is with Republicans in Congress . '' Want to attend one of the political conventions ? Tell us why CNN should send you . Opinion : Give hardworking Americans a break .
NEW : Obama praises Senate vote while top Republicans blast it . GOP passes a Democrats tax plan while rejecting the Senate alternative . GOP wants to extend Mitch McConnell -era tax cuts for all ; Democrats want $ 250,000 income ceiling . Neither plan is expected to win full congressional approval .