With President Biden out of the 2024 race, Democrats aren’t just hoping to win the presidency. They also believe they have a better chance to take the House of Representatives and keep the Senate.

Biden was a drag on the ticket. He ran behind congressional Democrats in polls. He could have cost his party otherwise winnable House and Senate races by causing Democratic-leaning voters to stay home. “Those voters were saying they really did want to vote for a Democrat, but they were super uninspired by Biden,” said Amy Walter, who tracks congressional races at The Cook Political Report. “And so they might not have shown up.”

Much of what Kamala Harris and Donald Trump would do as president depends on which party controls Congress. The race for the House is very close. The race for the Senate favors Republicans, but if Democrats forestall a wipeout, they could at least limit the G.O.P.’s agenda.

Today’s newsletter will break down the state of these consequential races.

House Republicans have an advantage in this year’s elections, but it is very small. According to The Cook Political Report, Republicans are favored in 210 seats. Democrats are favored in 203. A party needs 218 to control the House.

Among the 22 House seats considered tossups, Democrats and Republicans each currently control half. Republicans face a relatively easier task: They have to keep eight of their 11 tossup seats, without losing districts in which they’re favored, to win the House.