In theory,  a massive Republican victory in November would be the best thing for the country, at least what’s left of it. They could bottle up Barry’s judicial nominees for two years and stop his planned amnesty. Barry would be a lame duck and spend the next two years planning his retirement. The Republicans would do nothing to address the many things that ail the nation, but they would slow the decline.

On the other hand, a loss would throw cold water on Conservative Inc and the traitors in the Republican Party. The crew at National Review would be wearing black arm bands for a week. But, there’s the danger they draw the wrong lesson and lurch even further to the Left. If the 2010 election told them they had to try and compromise with Barry, they will find some way to snatch failure from a victory.

Democrats are now (very slightly) favored to hold the Senate majority on Nov. 4, according to Election Lab, The Post’s statistical model of the 2014 midterm elections.

Election Lab puts Democrats’ chances of retaining their majority at 51 percent — a huge change from even a few months ago, when the model predicted that Republicans had a better than 80 percent chance of winning the six seats they need to take control. (Worth noting: When the model showed Republicans as overwhelming favorites, our model builders — led by George Washington University’s John Sides — warned that the model could and would change as more actual polling — as opposed to historical projections — played a larger and larger role in the calculations. And, in Republicans’ defense, no one I talked to ever thought they had an 80 percent chance of winning the majority.)

So, what exactly has changed to move the Election Lab projection? Three big things:

* Colorado: On Aug. 27 — the last time I wrote a big piece on the model — Election Lab said Sen. Mark Udall (D) had a 64 percent chance of winning. Today he has a 94 percent chance.

* Iowa: Two weeks ago, the model gave state Sen. Joni Ernst (R) a 72 percent chance of winning. Today she has a 59 percent chance.

* Kansas: Republican Sen. Pat Roberts’s reelection race wasn’t even on the radar on Aug. 27. Today, Election Lab predicts that he has just a 68 percent chance of winning.

In addition to that trio of moves in Democrats’ direction, Louisiana has moved slightly in Democrats’ favor (from a 57 percent chance of losing to a 53 percent chance), as has North Carolina (a 97 percent chance of winning now as opposed to a 92 percent chance on Aug. 27).

The “data lab” at the Washington Post is a room covered in posters of Barry. Note that around this time in 2006 the GOP was making similar noises about polling. They were crushed two months later.