Impeaching the president is a popular topic among Democrats these days. But Republicans control both houses of Congress, so it seems like a futile endeavor without significant Republican support.
Have any Congressional Republicans so far said they support impeachment, or said what it would take for them to support impeachment, or what they consider impeachable offenses for this president? Additionally, is there any significant support by Republican voters for impeachment, or is this a purely partisan issue by Democrats right now?
ETA: I am asking about this president generally but I am most interested in Republican positions considering the firing of the James Comey, the president's admission that it was because of the investigation against himself (or his campaign, whatever), and the president's subsequent threat against Comey. And if any of that has had an effect on Republican support for impeachment.