Nikki Haley says military families can't trust Trump to 'keep them out of harm's way'

Former U.N. Ambassador Nikki Haley dug in Tuesday on her criticism of former President Donald Trump as unfit to hold the office again, arguing in an interview with NBC's Craig Melvin that Trump can't be trusted to protect America's military.

Against the backdrop of Trump's escalating attacks on her husband, who is serving overseas in the South Carolina Army National Guard, as well as his recent comments about NATO, Haley said those comments should make military families question whether Trump can be an effective commander-in-chief again.

“If you don’t know the value of our men and women in uniform. If you don’t know the sacrifice that they go through, why should I — as a military spouse and all our military families — trust you to know that you’re going to keep them out of harm’s way?" Haley said during the interview.

The interview will air on NBC's TODAY on Wednesday morning. An excerpt aired Tuesday night on NBC Nightly News with Lester Holt.

Haley has been criticizing Trump's conduct, record and positions more and more as the GOP nominating fight continues, with Trump looking to vanquish his final big-name rival and Haley trying to convince her party she can mount a comeback victory.

During a rally over the weekend, the former president told supporters he'd "encourage" Russia to "do whatever the hell they want" to a NATO ally that didn't pay enough to bolster the treaty organization's defense commitments. The comments drew outrage from Democrats and some corners of the Republican Party, but prominent Republicans defended Trump too, including Florida Sen. Marco Rubio, the top GOP member of the Senate Select Committee on Intelligence.

Jason Miller, a top Trump adviser, responded to the criticism over the weekend in