Retired Army Lt. Col. Alexander Vindman, a key witness in President Donald Trump’s impeachment inquiry, said Monday evening he has no regrets about delivering the explosive testimony that garnered fierce backlash from Trump and ultimately informed his early exit from the military.

“So I think that, in the end, I have no regrets about how things turned out. Yes, I left the military unforeseen. I had every intention staying on — going on to war college. But I think my role may have been, in certain ways, more important in that I was able to do my part — defend this nation in a very meaningful manner and expose corruption by the chief executive,” Vindman said during an interview on CNN’s “Erin Burnett OutFront.”

“I feel that in that regard that I have served my nation.”