While the 2020 presidential election has dominated the headlines, the races for U.S. Senate and the U.S. House of Representatives also could prove important for the future of national politics.

Virginia’s senior senator, Democrat Mark R. Warner, is facing a challenge from Republican Daniel M. Gade, a retired Army lieutenant colonel who teaches at American University.

Sen. Warner, a former Virginia governor who was first elected to the U.S. Senate in November 2008, serves as vice chairman of the Senate Intelligence Committee, where he has been an integral part of the investigation of Russian interference in the 2016 presidential election. He continues to push for greater regulation of social media and tech companies to protect user data and combat disinformation.

Mr. Gade has presented his campaign as a new voice against establishment politicians, touting market-based solutions to climate change, strong national defense and quelling crime in local communities. His campaign also has promoted individual liberties and rights.

While Sen. Warner has maintained a sizable lead in fundraising and in the polls, he is not taking the race for granted. In 2014, Sen. Warner narrowly won re-election in a race against GOP candidate Ed Gillespie.

With Democrats looking to take control of the 100-member U.S. Senate with this election, they must hang onto the 45 seats they currently hold.

Democrats hold a majority of the seats in the 435-member U.S. House of Representatives.

Rep. A. Donald McEachin of Richmond, a Democrat who represents the 4th Congressional District, is being challenged by Republican Leon Benjamin Sr., senior pastor of New Life Harvest Church in Richmond.

Rep. McEachin was first elected to Congress in November 2016, the same year court-ordered redistricting reshaped the district, giving it a profile that has favored Democrats. Rep. McEachin has campaigned on greater access to health care, ending gun violence and equity issues including access to broadband for rural residents in the district. He also has spotlighted his work on climate change and energy policy.

Rev. Benjamin, who serves as chairman of the Richmond Republican Party, has focused his campaign on promoting school choice, economic development and building Virginia’s science and technology industries. He is an outspoken supporter of President Trump and has served as an evangelical adviser to the White House.

By far the most contentious race is in Virginia’s 7th Congressional District, where Democratic Rep. Abigail A. Spanberger is facing GOP challenger Nick J. Freitas of Culpeper, a member of the Virginia House of Delegates since 2016.

Rep. Spanberger’s campaign has showcased her key accomplishments during her freshman two-year term in the U.S. House of Representatives, including her support for lower prescription drug prices and expansion of broadband access in the district.

Her campaign priorities have focused on health care costs, preventing gun violence, creating more jobs and helping to bolster the economy in the wake of the COVID-19 pandemic.

Delegate Freitas has centered his campaign on limiting government influence on individual liberty and personal responsibility.

In 2018, he sought the Republican nomination to run for U.S. Senate against Democrat Tim Kaine, but lost the primary to ultraconservative Corey Stewart of Prince William County.