In a new attack ad released by a Republican political group, Dr Dan Barkhuff chastises the president for his response to reports that Russia has allegedly paid bounties to Taliban-linked militants to kill US troops.
"Months ago, Donald Trump learned that the Russians were paying bounties for dead American soldiers in Afghanistan. He chose to do nothing about it," Mr Barkhuff says in the ad from the Lincoln Project.
The New York Times reported earlier this week that US officials had briefed the president and senior White House staff about the claims. The White House has denied that the president has been briefed.
"Any commander in chief with a spine would be stomping the living s*** out of some Russians right now, diplomatically, economically, or if necessary, with the sort of asymmetric warfare they're using to send our kids home in body bags," Mr Barkhuff said.
He then claims Mr Trump is either a "coward" or "complicit" for his inaction.
"Mr Trump, you're either a coward who can't stand up to an ex-KGB goon, or you're complicit. Which is it?" he said. "Donald Trump is unfit to be our commander in chief, and that's worse than useless."
Mr Barkhuff — who in addition to his military career labels himself a "pro-life, gun owning combat veteran" — has been critical of Mr Trump since at least 2018, when he founded a political action committee called Veterans for Responsible Leadership. Now an emergency room doctor, his work is focused on turning veterans and the general public away from the president.
During a 2018 appearance on "The Mid Pod" podcast, Mr Barkhuff was asked what an "irresponsible" leader looked like. In response, he described Mr Trump.
"Someone you can't trust. The short answer would be someone who doesn't take seriously the responsibility that they have. There is a saying in the military: 'you can delegate authority, you can't delegate responsibility.' That is true," he said. "And the current Commander in Chief for example, I think, is quick to point fingers at other people when something doesn't go his way and regularly engages in demonstrably untrue falsehoods."
The ad is the latest in a barrage of video spots released by the Lincoln Project, an ostensibly conservative PAC that is publicly dedicated to undermining Mr Trump's in the 2020 US election.
Among the group's leadership are former Republican strategist Rick Wilson, political consultant and former John McCain campaign staffer John Weaver, Republican comms operative Steve Schmidt and attorney George Conway, husband to infamous Trump aide Kellyanne Conway.
The group endorsed likely-Democratic candidate Joe Biden for president in a Washington Post op-ed published in April. The authors argued that Mr Trump's pandemic response and the resulting economic consequences were reason enough to remove him from office.
The Lincoln Project has released eight video ads since mid-March. The ads tend to focus on Mr Trump's alleged weaknesses both as a leader and as a moral actor.
Last month, the group released the ad "#TrumpisNotWell," which said the president was "shaky, weak" and that he had "trouble speaking, trouble walking." Images of the president drinking water with two hands were shown over the voice-over. Though the ad was called ableist for portraying people with physical disabilities as unfit leaders, it was shared widely across social media by liberals and Republicans critical of the president.
Mr Trump has called the group "RINO losers" — RINO being shorthand for 'Republicans in name only' — for not supporting him despite his perceived political victories.
Thus far, the Lincoln Project has spent $2.75m on TV ads and $1.2m on Facebook ads.
The Club for Growth Action, a conservative Super PAC aimed at curbing government regulations and keeping taxes low to maximise profits for corporations, called the Lincoln Project a "Democratic front group."
"The Lincoln Project has nothing to do with principle, and everything to do with lining the pockets of failed consultants by attacking conservatives," Dave McIntosh, the Super PAC's leader, said. "While the group is the darling of the liberal media, the fact is it's a Democrat front group and one of the least efficient ways for anti-Trumpers to spend their political dollars."
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies