House Republicans’ proposal to overhaul federal entitlement programs such as Medicare is set to encounter its first big test on the campaign trail this month in the special election for former congressman Chris Lee’s (R) Republican-leaning district in Upstate New York.

The contest to succeed Lee — who resigned in February after reports that the married House freshman sent shirtless photos of himself to a woman he met on Craigslist — has gone from a fairly sure thing for Republicans to a tight race, and one that has quickly become nationalized in the weeks since the Republican-led House approved its 2012 budget blueprint.

In a sign of the national significance that the May 24 election has taken on, House Speaker John Boehner (R-Ohio) was slated to hold a rare campaign-trail appearance Monday on behalf of the Republican nominee, state Assemblywoman Jane Corwin. Boehner was set to stump for Corwin at noon at an Italian restaurant in Depew, 10 miles outside Buffalo, hours before he is scheduled to unveil the GOP’s debt-limit strategy at the Economic Club of New York.

Meanwhile, a liberal Social Security/Medicare group is holding events in the district Monday afternoon on behalf of the Democratic nominee, Erie County Clerk Kathy Hochul. The National Committee to Preserve Social Security and Medicare will campaign with Hochul in Buffalo at 2 p.m.

The events come as Hochul has gone up with TV ads blasting Corwin’s support for Rep. Paul Ryan’s (R-Wis.) 2012 budget blueprint, which calls for sweeping changes to Medicare. The ads are the first of the 2012 cycle to directly turn the Ryan budget into a campaign issue.

Further complicating things for Republicans is the presence of businessman Jack Davis in the race. Davis, who is running as a third-party candidate on the Tea Party line, has the potential to throw the race in Hochul’s favor by drawing Republican support away from Corwin. Amid polls showing that the race is tightening, Corwin’s camp last week went up with a TV ad tying Davis to President Obama and House Minority Leader Nancy Pelosi (D-Calif.) – a redux of a familiar theme from the 2010 cycle.

While it bears repeating that there are dangers in over-analyzing special elections, the fact remains that the NY-26 race will be the first real political test of the GOP’s Medicare message (and Democrats’ counter-message). That – and the fact that the election comes as the White House’s deficit-reduction talks are beginning in earnest – is reason enough to keep close tabs on the race as it becomes increasingly nationalized in its final two-week sprint.