Republicans joined in a letter: 'A Call For American Renewal'
Signatures include former governors, ambassadors, and Republican Party chairmen
Demands party returns to a rational party, supports free minds, markets, people
Release comes a day after Republicans ousted Liz Cheney from leadership
They call for the nation to 'reimagine a party dedicated to our founding ideals'
The signers attack 'disenfranchisement of voters' and 'reject populism'
Former President Trump attacked them as 'losers' and 'RINOs'
Comes as Cheney won't rule out run for president to stop 'unfit' Trump