Gov. Andrew M. Cuomo was the epitome of the very establishment the Democratic left has been frothing against: He raised big checks from big corporate powers. He was a dynastic candidate seeking a third term. He talked about capping taxes and constraining spending.

And he won a resounding victory on Thursday.

Mr. Cuomo turned back a progressive primary challenge from the actress Cynthia Nixon in such emphatic fashion — he won by nearly the same margin as he had four years ago against a little-known and underfunded challenger — that by the next morning, he was back to being asked about 2020 presidential ambitions that he had flatly denied only weeks ago.

The victory was thorough. Mr. Cuomo carried Long Island with roughly 75 percent of the vote. He won the Bronx, his best county in the state, with nearly 83 percent support. His next best borough in the city was its political polar opposite: Staten Island. He flipped parts of the Hudson Valley that he lost four years ago by double digits.

“It was upstate. It was downstate, white, black, brown — it was across the board,” Mr. Cuomo said on Friday, ticking off his margin in particular districts, even as he said he hadn’t fully studied the numbers.