War-gaming the electoral college is the favorite pastime of pundits at this point in the campaign.  With less than 24 hours to go before the polls open, there are still a dozen states up for grabs – including some surprises on both sides.

For Donald Trump, it's a comeback of historic proportions.  Left for dead a couple of weeks ago, Trump has battled back into a competitive position and, according the Nate Silver, actually has a decent chance of winning:

All of this data is nevertheless consistent with Clinton being an Electoral College favorite. She has a 64 percent chance of winning the Electoral College in our polls-only model and 65 percent in polls-plus, putting her somewhere in the range of being a 2-1 favorite.

At the same time, it shouldn’t be hard to see how Clinton could lose. She’s up by about 3 percentage points nationally, and 3-point polling errors happen fairly often, including in the last two federal elections. Obama beat his polls by about 3 points in 2012, whereas Republicans beat their polls by 3 to 4 points in the 2014 midterms. If such an error were to favor Clinton, she could win in a borderline landslide. If the error favored Trump, however, she’d be in a dicey position, because the error is highly correlated across states.

Trump's one-in-three chance of winning is a surprise, given that Silver had Clinton at a 98% chance of winning just a few weeks ago.

What's changed?  Republicans are coming home.  Clinton hasn't lost much support, but Trump has gained millions of votes from Republicans who have decided they can't vote for Clinton and will hold their noses and vote for Trump.  And Trump's white working-class male support is making him extremely competitive in Rust Belt states like Michigan and Pennsylvania.

How competitive?  You can always tell how each candidate thinks the race is shaping up by where they spend the last few hours of the campaign. 

Hillary Clinton has events scheduled in Michigan, Pennsylvania, New Hampshire, Colorado, and Virginia – all states won by President Obama in 2012.  She also has events scheduled in North Carolina and Florida, which are both extremely close.

Trump will also be in Florida today but sees an opportunity in Michigan, Pennsylvania, and New Hampshire.  It is significant that neither candidate will be in the hugely important state of Ohio today.  Clinton is reportedly shifting staff from Ohio to Michigan.

The bottom line is that Clinton is campaigning in states that she should have already wrapped up – New Hampshire, Pennsylvania, and Michigan.  Trump is going for the jugular by trying to pick off each of those states.

And it is in Michigan where he may have the best shot.

The Hill:

If Donald Trump wins the swing state of Michigan Tuesday, he'll win the presidency, Republican National Convention (RNC) Chairman Reince Priebus said Sunday. 

It's an absolute toss-up," Priebus said on ABC's "This Week." 

"When you look at Michigan, where jobs have gone to Mexico and China, people are out of work and people want things to get better, I think Donald Trump is offering that vision for the state of Michigan. If we win a state like Michigan ... it's all over." 

A RealClearPolitics polling average gives Democratic presidential nominee Hillary Clintona 5-point advantage in Michigan, 48 percent to 43 percent. 

Priebus also said Trump, the Republican nominee, hasn't "turned away" from Wisconsin, even though he canceled a campaign event there to go to Minnesota. 

"It's possible he may go back to Wisconsin tomorrow," he said. 

With just a few days until Election Day, Priebus said he thinks momentum will carry Trump across the finish line. 

"I don't think we're fighting from behind. We've got momentum," he said. 

There hasn't been a Michigan poll for four long days, during which time the national polls have tightened considerably.  The fact that Trump and Clinton are both spending time there less than a day before the polls open suggests the race in Michigan is much tighter than the numbers show.

Is Priebus right?  Trump winning Michigan would force Clinton to win either Ohio or Florida to compensate.  Trump appears to be in good shape in Ohio and will have more than a fighting chance in Florida. 

But winning Michigan would signal a seismic shift toward Trump that would be reflected in other close states like North Carolina and New Hampshire.  In short, Michigan could be a bellwether that will signal whether or not Trump will be victorious.