When the US goes to the polls on 8 November, it won’t just be a test for those politicians seeking re-election, but also of President Joe Biden’s popularity.
The midterms take place every two years in the middle of a four-year presidential term. They include elections for all 435 seats in the House of Representatives and around a third of the US Senate (35 seats). There will also be contests in 36 states for governorships.
To have any real impact over the next 24 months, the White House needs the Democrats to keep control of the Senate. It is currently split 50/50, with Democratic vice president Kamala Harris casting a vote when the ballot is tied.
Retaining the Senate would mean Biden could appoint his chosen candidate to the US Supreme Court should a vacancy arise. These must be nominated by the President and then confirmed by the Senate.
The Senate also has the authority to ratify international agreements that do not relate to foreign trade. This could be significant if there is agreement on a new multilateral climate change treaty at next month’s UN conference in Egypt.
There is also the spectre of former president Donald Trump. These are the first national elections since 6 January 2021 when thousands of his supporters violently stormed the US Capitol building and many pro-Trump candidates are standing in the midterms.
Presidential parties tend to suffer defeats in midterms. Bill Clinton in 1994 and George W Bush in 2006 lost control of Congress (both the Senate and House of Representatives). To pass legislation at the federal level, bills must progress through both houses. This will become virtually impossible if, as expected, the House of Representatives switches to the Republicans.