Democrats are on track to win the House in Tuesday's midterm elections, the nonpartisan Cook Political Report says. The party could end up with as many as 240 seats, The Washington Post reported. That would be its largest House majority since 2009, the paper said.

A party needs 218 seats to control the House. Cook now favors Democrats in 222 races, and 18 more are toss-ups, The Washington Post reported. On Friday, Cook moved 12 more House races toward Democrats, the paper said.

Three races that had leaned Republican moved to toss-ups, The Washington Post reported. They include the seats held by Republican Representatives Brian Fitzpatrick of Pennsylvania and Jeff Crank of Colorado. Three seats rated likely Republican now only lean that way, including the seat of Indiana Representative Victoria Spartz, the paper said.

"If the bottom completely falls out for Republicans, Democrats could flip some seats in the Lean Republican and Likely Republican columns as well," wrote Erin Covey, Cook's House analyst, The Washington Post reported.

The New York Post reported that Cook now expects Democrats to gain 12 to 25 House seats. That would be enough to wipe out the narrow Republican majority and make Representative Hakeem Jeffries of New York the speaker, the paper said.

Democrats are also slight favorites to overcome the current 53-47 Republican majority in the Senate, The New York Post reported. By Saturday, Cook rated seven Senate races as toss-ups, the paper said. Six of them are in states that usually lean Republican, such as Kansas and Alaska, and one is in Michigan.

President Trump has held rallies in Republican-leaning states to boost turnout, The New York Post reported.

Cook's safer ratings have a strong record, The Washington Post reported. A review of its ratings since 1984 found that 97 percent of its "Likely" calls and 94 percent of its "Lean" calls turned out to be right.

What we know: Cook expects Democrats to win the House, possibly by a wide margin.
What we don't: How the 18 House toss-ups and seven Senate toss-ups will break on Tuesday.