With three weeks to go, Hillary Clinton is likely feeling pretty good, and here's why.

In the race for 270 electoral votes. she's ahead. That's based on an average of state polling on RealClearPolitics.com.

Right now all eyes remain on six key battleground states that will decide who wins.

In Florida, an average of polls show Clinton up by about 4 points, 46.4 percent to 42.8 percent. In Nevada, Clinton is up by about 4 points, too, 45.5 percent to 41.3 percent. In New Hampshire, Clinton leads 43.3 percent to 39.7 percent. In North Carolina, Clinton is up by 3 points, 46 percent to 43.3 percent.

Trump is leading in two battleground states of his own. In Iowa, he's up by 3 points, 41.7 percent to 38 percent. And in Ohio, Trump is up by about 2 points, 44.5 percent to 43.8 percent.

"He is simply trailing and trailing at a point that it's hard to believe he can make that up," said KHOU political analyst Bob Stein.

But here's why Trump has a more challenging path to victory. Even if Trump catches up in the battleground states and wins all of them, it doesn't get Trump to 270. Trump needs to take something on the electoral map that's blue and turn it red.

"Things can change, but it'll take extraordinary events," Stein said.

Trump can make a move in Pennsylvania or states like Wisconsin where he has been spending more time, but polls show him down in those states, too, and by wider margins than in the battlegrounds.

"There are states that I don't think anybody thought would be in contention," Stein said.

The Clinton camp is showing signs of confidence. They're working to expand the map. The campaign is investing time and money in Arizona, a state that hasn't gone blue since 1996, but polls show Clinton just down by 1 point there.

And Clinton is running ads in Texas now, although no one really expects Texas to turn blue this year.

"I think he has days or even hours to try and reverse this," Stein said. "I don't see how, but I've seen stranger things happen in American politics."

The bottom line is the 2016 election will swing one way or another based on what happens in six key states. When the candidates meet for their final Wednesday night, those are the voters they'll be targeting.