Conservative policies will work if they are passed. With a Republican House and Senate, which is likely in 2013, they will pass. That will make a President Santorum very popular.
We probably won't have a 60-vote majority in the Senate, so it will still be a challenge to pass legislation. And, as with Reagan it may take a few years for the effects to heal the damage from the previous administration.
Then, once conservative policies have fixed the economy, what happens next? The economy no longer is the number one thing on voters minds. Didn't matter with Reagan, because his entire positive outlook was one voters loved. But with Santorum's poor communication and defense of social conservatism, independents, who tend to be fiscally conservative, but socially liberal, might well swing back to Democrats.