Why are there only a few seats in the US Senate up for grabs? What you should know in 500 words | News about the 2024 US election

Thirty-four of the 100 total Senate seats will be contested in November, the result of a staggered electoral system.

One race has dominated this year’s election cycle in the United States: the battle between Kamala Harris and Donald Trump to win the White House.

But on November 5, Americans will also vote on filling other key posts outside of the presidency. Many of these races will determine who controls Congress, a key lever of power.

A third of the US Senate and the entire House of Representatives are up for election. This corresponds to 34 seats in the upper house of Congress and 435 in the lower house.

But why do representatives vote every two years – and senators every six years? And why aren’t all 100 seats in the Senate contested at the same time, like in the House of Representatives?

Staggered Senate races

The answer goes back to the country’s founding, when the men who wrote the U.S. Constitution decided to base Senate elections on a “three-tier system.”

A Senate fact sheet states: “At the beginning of the first session of Congress in 1789, senators were divided into the three classes by lot, with senators from the same state being assigned to separate groups.”

The first group’s term ended after two years, the second after four years and the third after six years.

“Subsequent elections for all classes were for a full six-year Senate term,” the fact sheet states.

The idea was to bring stability to US politics. Because of the Senate’s staggered voting system, two-thirds of senators remain in office in every national election every two years.

How does this compare to the House of Representatives?

The situation is different in the lower house of Congress, where all 435 members serve two-year terms and are eligible for election in every vote.

The need to run for re-election every two years makes House members more vulnerable to losing their seats.

Nevertheless, some representatives have been in the House of Representatives for decades: Former House Speaker Nancy Pelosi, for example, has been in office for 37 years.

What could happen on November 5th?

The Democratic Party currently only has a narrow grip on the Senate. The party and its allied independents hold 51 seats, compared to 49 seats held by Republicans.

To gain control of the chamber, Republicans will need a net gain of one Senate seat if Trump defeats Harris in the presidential race.

That’s because the vice president is the deciding vote in the Senate. If the Republicans win the White House, Trump’s vice president, JD Vance, would assume that role and vote with the Republicans.

If Harris wins, giving her Vice President Tim Walz decisive power, Republicans would need a net gain of two Senate seats to gain control.

Of the 34 Senate seats up for grabs next month, 23 will be held by Democrats or independents.

According to recent polls, there are likely to be some Senate races that appear to be neck-and-neck, including in the swing state of Michigan.

Republicans, meanwhile, hope to defend their control of the House of Representatives. There are currently 220 Republicans in the House, compared to 212 Democrats – with more than a dozen races considered to be tosses.