Republicans have blamed the Libertarian Party for two recent Democratic victories in the state Senate -- including John Morse (he won by 340 votes, the Libertarian candidate got 1320).
Colorado has a two step/one-day process (first an up or down vote on whether Morse stays or goes; followed by a replacement race with all candidates to succeed him). The Republicans have good reason to want to settle on one candidate and make the replacement race a one-on-one competition with a presumably unknown Democrat. Colorado does not have a primary for recalls (as far as I know, only Wisconsin has such a procedure). At the same time, we've seen in Michigan in 2011 that even a successful recall can backfire -- as a official was kicked out, but replaced by another Republican. We'll see if the Republicans can push out any challengers.