Here's the bad news: They don't want to put the Dems on their heels.
As long as they maintain Hillary as a threat, the GOp stays unified. As soon as the Dems become a totally marginalized force, an internal war immediately ensues on the right. Conservatives vs. Republican party types.
Rove knows this. He has a vested interest in a strong DNC opposition. This effectively puts the current GOP leadership at odds with the conservative movement.
Bingo. McCain is counting on Republican's fear of Hillary as his ticket to the nomination.