Hillary Clinton says Trump's behavior was 'embarrassing, if not illegal and impeachable'

Hillary Clinton stopped by The Late Show With Stephen Colbert Monday night, where she weighed in on the Trump impeachment inquiry.

"I believe strongly that this particular incident has had such a huge impact because we've known for a long time that he was a corrupt businessman who cheated people, and we've known that he and his campaign asked for aid from Russia, we've known that. But to see him in the office of the president, putting his own personal and political interests ahead of the national security of our country just pierced through whatever confusion or denial people had," said Clinton.

Moments before Clinton's appearance on the show, it was revealed that Secretary of State Mike Pompeo took part in Trump's phone call with the Ukrainian president. As former secretary of state, Clinton explained, "The secretary of state's job is to make sure that he knows, number one, what the president is going to say on those calls. I mean, these are usually very highly prepared calls and, you know, State Department, and Defense Department, everybody will send over, you know, talking points."

Clinton went on to explain that, generally, the president will have input on talking points. However, in Trump's case, Clinton stated, "You've got a president who doesn't listen to anybody and doesn't follow instructions whatsoever, I'm not sure they've even given up on trying to give him any sorts of preparation because they don't know what he's going to say."

Clinton explained that she believes the phone call was placed on "a highly classified system that is used for the most important secrets, like the Osama bin Laden raid, because even if there's nothing classified in it, the president's behavior was at least embarrassing, if not illegal and impeachable." Clinton also said she thinks if Pompeo was on the call, as it was reported, he would, and should, have been one of the first people to "clean" it up.

Colbert also asked Clinton — if she were still secretary of state, and the president was sending his personal attorney to handle foreign policy, how she would feel. Clinton stated that it would be a "big problem."

Clinton then blasted Rudy Giuliani, saying, "Presidents often use, as do secretaries of state, you know, they might use an envoy or a special advisor to deliver a message, but, again, it is supposed to be carefully thought through, and from what we've seen on television, carefully thinking through is not one of Rudy's strong points."

The Late Show With Stephen Colbert airs weeknights at 11:35 p.m. on CBS.

Check out Joe Biden’s response to Trump impeachment inquiry and Giuliani’s allegations:

Read more from Yahoo! Entertainment:

• Kamala Harris calls for Trump to be suspended from Twitter after ‘civil war’ tweet

• Leonardo DiCaprio’s response to Trump’s ‘insulting’ tweet to Greta Thunberg

• Rudy Giuliani fires back at his critics from both sides of the aisle

Tell us what you think! Hit us up on Twitter, Facebook, or Instagram, or leave your comments below. And check out our host, Kylie Mar, on Twitter, Facebook, or Instagram.