House Minority Leader John Boehner will take his bus tour into Democratic territory next weekend to boost Missouri Republican Ed Martin's congressional campaign.

According to an invitation obtained by RealClearPolitics, Boehner will headline a barbecue on the evening of Saturday, Sept. 4, in the ironically named Town & Country, a suburb of St. Louis and the wealthiest area of the Show-Me State. The invitation calls for a $250 donation per couple.

Boehner's visit follows one made last month by the House GOP's Chief Deputy Whip, Kevin McCarthy of California, and two last year by National Republican Congressional Committee Chairman Pete Sessions of Texas. When contacted about the visits by Republican lawmakers and asked if House Minority Whip Eric Cantor has scheduled a St. Louis stop, Martin said nothing is in the works.

Martin is challenging Democratic Rep. Russ Carnahan, who represents the left-leaning urban district. According to a new third-party poll, the race is becoming competitive.

Carnahan's campaign has been unlucky this cycle already: His was the first campaign to endure Tea Party-fueled violence last summer when town hall meetings across the country spiraled out of control for some members. And the St. Louis Post-Dispatch reported that a firebomb was lodged into his campaign office just last week.