Senate Republicans on Wednesday stood by a GOP plan to transform Medicare, one day after the party lost a conservative House district in Upstate New York amid a strong effort by Democrats to make that proposal the central issue. The measure was defeated in the Democratic-run Senate on Wednesday. But the unity among Republicans — with only five out of 47 voting against it — served as an important sign that party leaders remain wedded to a deficit-reduction plan that is a loyalty test for many GOP voters but is widely unpopular, according to polls. Wednesday's vote underscored the pressure being exerted by the party's tea party base to stick with the plan, sponsored by House Budget Committee Chairman Paul Ryan (WI), and the calculation by Republican officials that they have time before the 2012 election to neutralize any of the Democrats' political advantages. Moreover, in the Senate, the GOP has some breathing room, with only 10 members up for re¬election next year and just one considered vulnerable.