From CNN's Zachary B. Wolf
The real question on Election Day is whether Republicans can hang onto their slim majority in the Senate.
Democrats need to pick up a net of three seats if Biden wins and four if Trump wins (the vice president breaks ties in the Senate) to seize power.
They're pretty much guaranteed to lose a Senate seat in Alabama, so Democrats are looking for 4-5 seats elsewhere. There are plenty of opportunities.
One Republican-held seat — Colorado — is rated by CNN as "lean Democratic."
Three Republican-held seats — Arizona, Maine and North Carolina — are rated by CNN as "tilt Democratic."
Three Republican-held seats — Georgia, Iowa and Montana — are rated by CNN as "tossup."
If there's a massive Democratic wave, look to the three Republican-held seats — Kansas, South Carolina and Georgia's second seat — rated by CNN as "tilt Republican."
Meanwhile, Democrats are expected to build on the House majority they won in 2018.
Check out the full ratings here.
CNN's Phil Mattingly explains:
Voters across the country today will decide more than who will sit in White House. States will weigh several different issues this election, such as whether to legalize marijuana, limit access to abortion, reform voting and more.
Here are some of the top ballot measures to watch this Election Day: