Republican Trump critic Jeff Flake is retiring after 2018

Arizona Republican Sen. Jeff Flake (Gage Skidmore / Flickr CC)

Arizona Sen. Jeff Flake announced today he will not run for re-election after his current term, per AZ Central.

Why it matters: Flake's vacant seat will make it even harder for Republicans to maintain their majority control of the Senate — this now makes two Republicans, both consistently attacked by Trump, who have declared they're not seeking re-election.