While there is no evidence that a national partisan wave will develop between now and Nov. 6, there is every reason to expect a number of "state waves" that will prove to be challenging for some candidates - and for political handicappers.
In fact, candidates' abilities to fight through the waves in a handful of states could well determine which party controls the Senate.
In a number of Senate contests, a strong candidate faces the daunting task of running 10 or 15 points ahead of his or her party's presidential nominee. That isn't impossible, but it certainly is challenging.
For Sen. Scott Brown in Massachusetts, Heidi Heitkamp in North Dakota, Sen. Jon Tester in Montana, Rep. Joe Donnelly in Indiana, Linda Lingle in Hawaii and Linda McMahon in Connecticut, the fundamental political landscape in their states is not flat. Instead, it's strongly tilted against them.
Then-Sen. Barack Obama won Massachusetts by more than 25 points and Connecticut by more than 22 points in 2008, and while his victory margins are likely to be smaller this time, he will still carry both states comfortably. The same goes for the state where he was born, Hawaii, which he carried by more than 45 points four years ago.
Obama lost North Dakota four years ago by almost 9 points while he was winning nationally by more than 7 points, and this time the president is likely to lose the state far more resoundingly. In 2000, in a very close contest nationally, George W. Bush defeated Al Gore by more than 27 points in the Peace Garden State.
Two states that saw close races in 2008 appear likely to blow open this time. Obama lost Montana by just over 2 points four years ago, but a double-digit win in the state by Mitt Romney seems in the cards this year. Neither Gore in 2000 nor John Kerry in 2004 drew even 40 percent of the vote in Montana.
And while Obama won Indiana narrowly in 2008 (by a single point), nobody on either side of the aisle expects a tight presidential contest this time. Another double-digit GOP win, much like 1988, 2000 and 2004, seems likely.
Brown, Heitkamp, Lingle, Tester, Donnelly and McMahon all know that to win election to the Senate they will have to win despite their presidential nominee's showing, not because of it.
Interestingly, in at least four of these contests - and maybe even in all six of them - the candidate who must overcome a partisan disadvantage this year is the better candidate and is running the better campaign.