OUCH: Republican releases ad promising to ‘stand up’ to Trump.

The commercial, from GOP Rep. Mike Coffman of Colorado, represents the first time a House Republican has used explicitly anti-Trump messaging in paid advertising. It comes as many in the Republican Party — concerned about Trump’s impact on down-ballot races — are grappling with whether to take further measures to repudiate their presidential nominee after a string of controversies including an attack on a Gold Star family and his refusal to endorse House Speaker Paul Ryan in his primary.

The 30-second ad opens with a shot of Coffman, a 61-year-old Army and Marine veteran who fought in Iraq, looking directly at the camera.

“People ask me, ‘What do you think about Trump?’” he says. “Honestly, I don’t care for him much.”

A few moments later, he says: “I’m a Marine – for me, country comes first. My duty is always to you. So if Donald Trump is the president, I’ll stand up to him. Plain and simple.”

Coffman’s district has long been a GOP stronghold, but redistricting in 2012 (Cook PVI D+1) turned it into a tossup.