Transcript for Arizona Republican senator calls GOP 'toast' on open mic

From tax reforms dubbed brass tacks on the beach of the Republican Party. Just seconds after senator Jeff flake had finished a town hall on tax reform. He's still on open Mike chatting it up with Republican ally may sound there John giants. Come the party of Roy Moore. And Donald Trump. Regarding the host and our actual smoke that's that you're at the guys that could just. Much. Just to keep the four you know and to point out what in the audience that's. OK you know and it. Just then another man points to the senators lapel Mike and realization washes over Jeff flakes face. After the conversation that the man out prodding the senator here to run for president apparently referring to Donald Trump as idiot. Giles had just minutes earlier asked lake about the possibilities for 2000 money you can see the mayor highlighted here at the front of the body and. Saint senator flake of I think with the flick can we start the presidential campaign today if there's. Anybody anything anyway we can encourage you to. Think again about the prospect of doing the. Mesa a Republican stronghold that went more than 53% for trop last year big bump over the 49%. He won statewide. There could be political ramifications for the mayor speaking out against the president that's gonna hurt all of this could also be an indication of how well armed Republican elected officials are about the direction their party. You can tell there's there's smoke rising from the GOP now whether another lease on a mile fire alarms a little crazy scene but again I think folks we're we're just losing a lot of indicators right now. That are leading to not so pretty picture for Tony eighteen.

This transcript has been automatically generated and may not be 100% accurate.