BBC correspondent: Historic victories for Democrats as they push deeper into Republican strongholds

Tonight is shaping up to be truly historic for the Democrats, as the party has won control of the US House of Representatives and is also on track to seize control of the Senate.

Democrats achieved their first upset victory in the Senate, when Annie Andrews defeated Darlene Graham, who had been appointed to the seat after the death of her brother, prominent Republican Senator Lindsey Graham.

Even just a few months ago, few analysts expected this seat to be contested.

Also, two races for Senate seats that were thought a year ago to be equal arenas for competition turned into two easy victories for the Democrats, with the re-election of Democrat Jon Ossoff in Georgia, and the capture of the vacant seat that was occupied by Republicans in North Carolina.

The North Carolina contest, where former Democratic Governor Roy Cooper defeated Michael Whatley, a Republican Party icon, was the first of four gains that Democrats need to regain control of the Senate. After the win in South Carolina, they are more than halfway there.

Attention has now turned to the counting of votes in Republican-controlled Senate seats in Texas, Kansas and Ohio.

CBS News, the US partner of the BBC, classifies the Senate races in Texas and Kansas as leaning in favor of the Democrats. The governor's race in Texas, where Republican Greg Abbott, the current governor, was considered the overwhelming favorite just a year ago, is now seen as too close to predict its outcome.

At the same time, Democrats won a majority in the House of Representatives for the first time since 2022.

A look at the most prominent races provides many reasons to explain this.

In Florida, Republicans in the state legislature redrawn the boundaries of three Democratic districts, making them much easier for Republicans to win, but they lost all three districts.

Other House of Representatives races in the state, which Republicans had expected to win by comfortable margins, turned into heated electoral battles.

For example, Democrats picked up open seats in western North Carolina and Kentucky, and appear well positioned to make gains in Virginia and Indiana.

They are doing this by benefiting from the high participation of Democratic voters, especially black voters in the South, as well as the recovery of Latino voters in Florida, who had supported Republicans just two years ago.

In South Carolina's majority-black counties, Democratic Senate candidate Annie Andrews performed much better than Kamala Harris in the 2024 presidential election.

In Miami-Dade County, which Trump won that year, Democratic candidates returned to the lead.

If there is a silver lining for conservatives, Florida as a whole still appears to be leaning to the right.

Republican Senator Ashley Moody narrowly won re-election, as did Congressman Byron Donalds in his bid for governor. But this state may prove to be one of the few bright spots.

While the mood of voters appears to have turned against President Donald Trump and Republicans broadly, the United States is a vast country with unique geographic and demographic characteristics.