Republicans would likely see 2004 as a fluke as Bush was still extremely popular with the base at that time and I doubt Kerry pulls out a win in both the popular and electoral vote unless Bush's term is significantly worst than OTL. Kerry has a hellish term that consists of a hostile Republican Majority in Congress throughout the entire term, Katrina, which is handled better than OTL, but not enough to where Kerry goes unscathed from it, the fallout in Iraq and Afghanistan (which he's wrongfully blamed for), rising gas prices, and the worst economic downturn since the Great Depression. Kerry would be seen as Carter 2.0 with would be Vice President Edwards possibly adding a little twist of Clintonian scandal. 2008 would be 1980 2.0. McCain and a Republican Congress probably worsen the effects of the Great Recession as economics wasn't McCain's strong suit and a GOP supermajority forces austerity on the Country. A McCain administration is also likely to be a thorn in the ass of our allies to, so President Hillary Clinton or President Barack Obama, which ever makes President McCain a one termer, is going to have a lot on their plate come January 2013. I also think what
@Inferus said here is true:
Very likely this series of modern day presidencies shows a great deal of political shift and a country divided. The country is going to have severe issues dealing with terrorism, the economy, etc as the Executive's focus continually swings every four years
I think even if a Democrat elected in 2012 wins in 2016, much of this divide and the issues dealing with terrorism and the economy would remain true as even if the executive holds, the Congress is likely to swing Republican in 2014.
The bigger impact will be in the change in policies from President to President, not that we'd have multiple one term Presidencies in a row which is fairly common. From 1953 to 1989 only two Presidents - Ike and Reagan - were elected to two full terms. In fact, having every President from 1993 to 2017 be re-relected is what's unusual.
I don't think we'd see a huge change in policy until 2012 in TTL. Kerry would be blocked from making change at every turn by a Republican Congress and McCain with a Republican supermajoirty wouldn't be all that different from Bush. Also, I'd like to add that Ike and Reagan were the only two from '53-'89 that were elected to two full terms AND Finished them. Nixon was also elected to a second full term, he just didn't finish the second like Ike and Reagan did.