When the dust settles after the November 3 United States elections, both major political parties hope they will have taken control of the 100-member Senate, a body that has outsized power in influencing American life beyond its legislative role.
Republicans currently hold a 53-47 majority in the chamber, but 35 seats will be up for grabs on Election Day. Twelve of those are currently held by Democrats and 23 are held by Republicans.
Analysts generally favour Democrats’ chances of taking control of the Senate, to which each of the 50 states elects two senators to serve six-year terms in staggered elections every two years.
The Senate and the 435-member House of Representatives together make up the US legislature, also known as Congress.
This election cycle, at least 14 Senate races are considered competitive, according to the Cook Political Report, with 12 Republican incumbents facing formidable challenges. Meanwhile, just two Democratic incumbents’ re-election chances are considered imperilled.
Democrats have high hopes that Mark Kelly in Arizona and John Hickenlooper in Colorado will unseat Republican incumbents in those states, while Republicans are optimistic candidate Tommy Tuberville will defeat Democratic incumbent Doug Jones in Alabama.
Earlier this week, Senate Republican Majority Leader Mitch McConnell, who is expected to win his re-election bid in Kentucky, called the Republican likelihood of holding onto the chamber a “50-50 proposition”.
Because the US vice president serves as a tie-breaking vote in the Senate, Democrats will have to win at least four seats to have a majority if President Donald Trump wins re-election.
If Democratic presidential candidate Joe Biden wins, the party will need to gain just three seats to take the majority because Kamala Harris, Biden’s vice-presidential nominee, would become the tie-breaking vote.
Such a victory would represent a sweep for the party, as the House is widely expected to maintain its Democratic majority.
Here’s what else is at stake in the Senate elections.
The Senate plays an important role in introducing and passing federal laws. Both the Senate and the House of Representatives must approve legislation before it is brought to the president to sign into law.
The president, meanwhile, can veto that legislation. However, such a veto can be overruled by a three-quarters majority vote in both chambers of Congress.
A party that controls the House, the Senate, and the presidency, therefore, has a rare ability to pass laws largely unencumbered by an opposing party. Those laws, however, are still subject to legal challenges.
The Senate, like the House, also has the ability to launch investigations into the Executive Branch on matters of public interest. It can also compel individuals, groups, or agencies to submit relevant documents to the investigation.
While such investigative powers are not specifically outlined in the Constitution, they have been recognised since 1792.
Beyond passing laws and launching investigations, the Senate holds several more unique influential powers.
Most notably, the chamber approves treaties and confirms cabinet secretaries, ambassadors, and federal judges, including life-serving Supreme Court justices, nominated by the president under its “advice and consent” role outlined in the US Constitution.
The Senate also conducts trials of federal judges and “civil officers” in the US government, including the president and vice president, if they are impeached by the House.
Trump has enjoyed a Republican-majority Senate since taking office in 2017.
The chamber has appointed several controversial cabinet officials, three Supreme Court justices chosen by the president, and a wave of conservative, lower-level federal judges that critics have said will ideologically shape the US justice system for years to come.
In February, the chamber moved to acquit Trump of abuse of power and obstruction of Congress after the House impeached him on the charges at the end of 2019. The vote came along party lines, except for one Republican who broke ranks.
The Republican Senate has also protected Trump from congressional attempts to reverse his executive actions, and blocked legislative proposals by the Democrat-controlled House.