The former head of the U.S. Office of Government Ethics urged the American public on Friday to pay careful attention to everything that’s going on with President Donald Trump’s administration.

“Heed the signs and don’t underestimate the threat to our republic from within,” tweeted Walter Shaub, who served in the high-ranking role under former President Barack Obama and then for six months under Trump until his resignation in July 2017.

In a 14-tweet thread, Shaub detailed the “signs” that should be noticed from Trump’s time in the White House ― from the president’s 10,000-plus lies since his inauguration to his controversial declaration of a national emergency in a bid to secure funds for his proposed wall on the U.S.-Mexico border.

Shaub has previously warned that the White House is currently suffering an “ethics crisis” that could make the U.S. look like “a kleptocracy.”

Check out Shaub’s full thread here: