A former White House press secretary under President Bill Clinton urged Democrats to forgo impeaching President Trump because, he said, keeping him in office will obliterate the Republican Party.

“Mr. Trump is three years into destroying what we know as the Republican Party. Another two years just might finish it off. Trumpism has become Republicanism, and that spells electoral doom for the party,” Joe Lockhart, Clinton’s press secretary from 1998 to 2000, wrote in a New York Times op-ed published late Monday night.

[Related: Lindsey Graham: Democrats will ‘stampede’ to impeach Trump using Mueller report]

Former White House press secretary for President Bill Clinton, Joe Lockhart. (Pablo Martinez Monsivais/AP)

Lockhart argued Trump deserves to be impeached because he is unfit for office, but allowing him to finish his term will be more beneficial to Democrats because the Republican Party has become the party of Rush Limbaugh, Sean Hannity and Tucker Carlson, and will push more voters to back Democrats.

A push for impeachment would only end up uniting a “fraying” Republican Party, Lockhart said, citing Democrats’ election successes after Clinton was impeached.

“Allowing Mr. Trump to lead the Republican Party, filled with sycophants and weak-willed leaders, into the next election is the greater prize. Democrats have a once-in-a-lifetime opportunity to realign American politics along progressive lines, very much like Ronald Reagan did for Republicans in the 1980s,” he said.

“Trumpism equals Republicanism as long as Donald Trump is at the top of the ticket. And a real shift to progressivism in America will be delivered by a devastating rebuke of the president and his party, a rebuke that will return control of the Senate and state houses across the nation. Politics is always a gamble — and this is the best bet we’ve had in a long time,” he continued.

House Speaker Nancy Pelosi has thus far dismissed the prospect of impeaching Trump. In a call with her colleagues Monday, she said Democrats instead would focus on investigating Trump.

[Opinion: Here's why impeachment talk is dangerous for Democrats]