President Trump's military naivety is showing.

When Lt. Col. Alexander Vindman and aide to Vice President Mike Pence Jennifer Williams testified for the impeachment inquiry Tuesday, Vindman, an active member of the Army, showed up in his dress uniform. That's explicitly required under Army regulations, but it didn't stop Trump from questioning his outfit choice anyway.

Vindman heads European affairs for the National Security Council and is also a decorated Army officer who earned a Purple Heart while fighting in Iraq. So as an active member of the U.S. Army, he's beholden to the regulation that dictates he wear a "service or dress uniform" when asked to wear "business attire." Testifying for Congress would certainly fall under that dress code, as an Army spokesperson confirmed. But Trump seemed skeptical of that on Tuesday when he said "now [Vindman] wears his uniform when he goes in," probably referencing the fact that Vindman wears civilian dress, as is regulation, when he goes to work at the National Security Council.

After Pres. Trump's comment on Lt. Col. Vindman wearing a military uniform to testify today, an Army spokesperson tells @ABC News: "A soldier performing duties in an official capacity will normally be in uniform."



More from @MarthaRaddatz: https://t.co/wJIckfThSv pic.twitter.com/IeHKrkfBMt — ABC News (@ABC) November 19, 2019

Rep. Chris Stewart (R-Utah) also brought up that Trump and Ukraine's President Volodymyr Zelensky both lack military backgrounds, and suggested Vindman shouldn't have interpreted Trump's request for a Biden investigation as a "demand." But Trump's military inexperience doesn't negate the fact that he's the commander in chief of the armed forces regardless of his lack of military background. Kathryn Krawczyk