Republican urges conservatives to run against Donald Trump in 2020

A Republican senator said Sunday that a conservative should run against US President Donald Trump for the party's presidential nomination in 2020.

Jeff Flake, a vocal critic of the president, said he did not think he would run but that someone else should.

"I have said all along that somebody needs to run on the Republican side, if nothing else, to remind Republicans what it means to be conservative, what being a conservative really means, and what it means to be decent as well," he said in an interview with CNN's "State of the Union."

Flake, who is leaving the Senate in January, warned that in his state of Arizona, a Republican bastion in the past, voters are rejecting candidates "tied at the hip with the president."

"And I think that we're seeing that elsewhere in the country as well. We're losing the suburbs," he said. "If we had a mass movement from the suburbs for people to move back to rural areas, then perhaps our Republican Party would have more of a future -- but not the way that we're going now."

Democrat Kyrsten Sinema was elected in this month's midterms to the Senate seat Flake is vacating, defeating Martha McSally, a former air force pilot who embraced Trump.  

Trump has said he is "100 per cent" certain he will run for a second four-year term in 2020.