I have long believed the pundits have it wrong (as they often do J ) on whether the Senate will flip to the Republicans, in their gloom and doom scenarios.  Mostly my view on this is because the press and pundits have so badly understood the Affordable Care Act (ACA) for so long, and how the public views it, and how it will be viewed by November.  In particular, I think the popular press view is that ACA is very unpopular and that therefore the Democrats and incumbent Senators will be punished.  However, this is a misreading of the polls.  The truth is that a majority of the public does not want the ACA repealed, they want it retained, but perhaps modified to fix some of the glitches in the legislation.  A hard core does not like the law and wants it repealed--but those folks are core of the Republican vote anyway and they have long hated the ACA.  

So along with all this take a look at the
recent POLITICO predictions of how the Senate election will turn out. chart of how Senate looks.  As they show it, looking at a snapshot today, if we put together uncontested seats plus safe seats plus likely seats, the Republicans start with a big advantage of 47-45 (because after all this is 2014, and six years ago Obama got elected).  Two seats lean Dem (MN Franken and CO Udall) and one leans Repub (GA Chambliss), so that puts it at 48-47 before we get down to the really competitive final five: IA, LA, NC, AK, AR.

Politico shows that Dems lead in three of these states in recent polls: NC, LA, AK, and I frankly have thought these candidates will win these states (except Alaska where I think Begich has a very tough fight on his hands, though he leads now).  Politico shows the Repub leading in Arkansas (though it is very close 47-43%).  So if those states go that way, it would be R 49, D 50 and Biden would have to cast tying votes all the time.

That leaves Iowa to give the Dems the time-breaking 51
st vote, or the Repubs their 51st vote, and their chance to give them majorities on all the committees (probably the most important factor, since Congress passes no legislation these days).  The latest poll has the Iowa race dead even at 43-43% with 14% undecided.

Or there is a real strong chance the Senate could be R 50, D 50 and Vice President Biden would have to cast the tie-breaking vote quite often!

There you have it.  Wow -- a very close Senate election, and one possible scenario, one very likely scenario is that Joe Biden may end up spending the last two years of the Obama presidency spending a lot of his presiding over the Senate, casting a lot of tie-breaking votes!