Even as he faces impeachment by Congress and possible removal from office, President Donald Trump's supporters appear to be standing by their man.

Trump now leads his top Democratic rivals, a new USA TODAY/Suffolk University Poll finds.

The national survey showed Trump defeating former Vice President Joe Biden by 3 percentage points, Vermont Sen. Bernie Sanders by 5 points, and Massachusetts Sen. Elizabeth Warren by 8 points.

And in hypothetical faceoffs, Trump also led South Bend, Ind., Mayor Pete Buttigieg by 10 points and former New York City Mayor Michael Bloomberg by 9.

The poll's findings seem  to suggest Trump's current travails and the withering criticisms of him are not undermining his standing with his political base. What does Trump know, or what is he doing, to earn this loyalty?