What to watch for on Election Night

CNN chief political analyst Gloria Borger: How will the white vs. nonwhite vote split

One important indicator I will be looking at Election Night is the question of ethnicity -- and how the white vs. the nonwhite population splits. In the 2008 election, 74% of the electorate was white. That percentage has declined recently because of the growth in the Hispanic and voting African-American population.

Given the ongoing Republican trouble with Hispanic voters and the assumption that African-Americans will, once again, vote overwhelmingly for the president, Mitt Romney needs a strong white turnout to help propel him to victory.

In an analysis by Republican pollster Bill McInturff, the question of the white/nonwhite divide is called the most "critical" of the election. His analysis shows that if the white percentage of the electorate drops to 72%, Obama will probably win the election.

One key to watch is how the white vote itself splits between Obama and Romney.

In the latest national poll CNN/ORC International, taken from Friday to Sunday, Obama received 40% of the white vote while Romney got 57%. In 2008, Obama received 43% of the white vote, which means he is polling less than that currently.

CNN chief political correspondent Candy Crowley: Virginia suburbs and I-4 corridor

The first thing I'll watch is the exit polls to see who's voting and where -- in particular, heavy Latino turnout in Colorado, Nevada, Virginia and Florida could indicate Obama wins those states.

Then, it's Virginia, Florida and Ohio.

I'll watch the Virginia suburbs of Washington, particularly the female vote. Romney won't win here, but he has to hold down Obama's numbers while running up his own score in the rural area. Romney has to win Virginia.

Florida is all about the Interstate 4 corridor. North of it votes Republican; south of it votes Democratic. The I-4 corridor decides.

Everyone will tell you to watch Lake, Stark and Hamilton counties in Ohio. There are good reasons to watch all of them, reasons no doubt delineated by my colleagues. But for me, it's all about Ottawa County, which has correctly picked the presidential winner in Ohio since 1944. That's a better record than pollsters. I'll watch Ottawa.

CNN political reporter Peter Hamby: How goes Pasco? 

Polls begin to close in Florida at 7 p.m. ET, and a handful of counties will report their absentee and early vote tallies immediately.

Once that happens, political pros in Florida will be anxiously refreshing election board websites in a handful of those counties -- Pinellas, Duval, Orange -- in search of early clues about which way the state is trending.

One of them is Pasco County, outside of Tampa. Officials there are diligent about posting returns as quickly as possible. The county has a slight Republican tilt, but Obama won the early and absentee vote there in 2008 despite losing the county on election night. For Democrats, it was a promising sign that Obama was well on his way to being competitive statewide, even in GOP-leaning areas.

In 2004, George W. Bush beat John Kerry in the Pasco early/absentee vote by 8 points. Bush ended up winning the county by 10 points. In a shift four years later, Obama beat John McCain by 5 points in the early absentee vote. He ultimately lost the county -- but only by 3.5 points, thanks to the votes the campaign banked early.

If Obama is losing Pasco by more than that Bush/Kerry margin by the time the first returns are posted, it could be a tough night for Obama in Florida.

"If you are looking for good news for Romney out of Pasco, if they have a 10- to 12-point lead in the absentee and early vote, that probably portends that they are going to have a really good night in suburban counties," said one top Florida Democrat.

CNN chief national correspondent John King: The suburban vote and who votes in the swing states