WASHINGTON — Need evidence there’s no clear path to the Republican presidential nomination? Consider the competing messages some likely candidates delivered on Sunday’s talk shows.

Wisconsin Gov. Scott Walker, relatively inexperienced on foreign policy, and Sen. Lindsey Graham of South Carolina, a veteran on the issue, appeared open to sending U.S. ground forces to take on Islamic State militants. At the same time, former Arkansas Gov. Mike Huckabee was trying to win voters by likening being gay to using alcohol or profanity.

Each approach could ultimately prove successful; both highlight the challenge for the crowded field of potential contenders to stitch together a winning coalition of national security hawks, evangelicals, social conservatives, business leaders and moderates who make up the modern Republican Party.

Each prospective candidate is testing appeals to voters and donors. The Iowa Poll, conducted last week for The Des Moines Register and Bloomberg Politics, showed Walker atop the list of potential candidates but statistically even with Huckabee, Sen. Rand Paul of Kentucky and 2012 nominee Mitt Romney when likely caucus-goers were asked their top choice. The poll was taken before Romney announced he was not running.