Rep. Greg Walden, chairman of the National Republican Congressional Committee, announced Monday that he will not support a resolution to authorize limited military strikes on Syria, marking a major blow to efforts to approve such a measure in the House.

"Absent a direct threat to the United States or our allies and a clear goal and definition of victory, I must oppose using military force in Syria," Walden said.

As the leader of House Republicans' campaign arm, Walden's announcement could influence what other undecided House Republicans do on the issue.

Walden's stance also runs counter to that of House Speaker John Boehner, R-Ohio, and Majority Leader Eric Cantor, R-Va., who have both said they would support the military intervention sought by President Obama.

The debate over how and whether the U.S. should respond to the Syrian government's use of chemical weapons against its own people has not unfolded cleanly along party lines, and many political observers doubt it will factor significantly into most mid-term elections next year.