While possibly effective, there's a danger to promoting a candidate from a different party, but that's not stopping the Arizona Democratic Party.
From the Espresso Pundit:
Wow, talk about a desperate move by those whose ideas have been rejected by the populace. The Arizona Democratic Party is sending out mail advocating for the Libertarian Candidate in CD 8 because he is the "Real Conservative."
That's an official concession in the battle of ideas. When the Democrats have a candidate as attractive as Gabby Giffords and instead of arguing that her world view is better than Jesse Kelly's world view—they argue that Steve Stolts [sic] is actually more conservative than Kelly, the Dems have shown that ideas don't matter, and they simply want to win elections.
While the argument could be made that both parties "simply want to win elections," it's hard for a party to stay idealistic when they're making a case for someone other than their own candidate.