Representative Paul D. Ryan’s eight terms in Congress have produced much political celebrity and Republican respect but just two laws bearing the Ryan name — a renamed post office and a modified excise tax on arrows like the ones he uses for bow hunting.

Then on Tuesday he struck a budget deal with Senator Patty Murray, Democrat of Washington, that affixed a new label to the polished veneer of Mr. Ryan, a Wisconsin Republican: deal maker and, to some, traitor.

With a modest, bipartisan blueprint on taxes and spending, Mr. Ryan is taking a risk he has previously shied away from, putting what party leaders see as a crucial need — ending the debilitating budget wars in Washington that have crippled the Republican brand — over his own self-interests with the conservative activists that dominate the early Republican presidential primaries.

For the first time, the conservative wunderkind and former vice-presidential nominee is taking withering fire from movement conservatives who see the deal as a betrayal by a former ally. Potential rivals for the Republican presidential nomination in 2016 immediately went on the attack, blasting the deal and challenging Mr. Ryan’s status as the thinking man’s conservative.