Former FBI Director Robert Mueller, special counsel on the Russia investigation, leaves following a meeting with members of the Senate Judiciary Committee in June 2017. Saul Loeb/AFP/Getty Images hide caption
Rep. Elizabeth Esty, D-Conn., at a news conference in 2013. On Monday the three-term congresswoman announced she will not seek re-election in 2018. Tom Williams/CQ-Roll Call,Inc. hide caption
Hillary Clinton, seen at a 2017 event in New York, recent appeared at a conference in India and talked about the 2016 campaign, saying that she won areas that were hopeful and Trump spoke to voters' racial and gender intolerance. Craig Ruttle/AP hide caption
Supporters of Democratic congressional candidate Conor Lamb await results on Tuesday night in Canonsburg, Pa. Lamb and Republican Rick Saccone were locked in a race that was declared too close to call hours after polls closed. Drew Angerer/Getty Images hide caption
Rep. Dana Rohrabacher, R-Calif., seen in 2013, stands out in the Republican Party for his urging of closer ties with Russia. Under the cloud of investigations over Russian meddling in American politics, he's being challenged over that stance in his re-election campaign. Lauren Victoria Burke/AP hide caption
Texas land commissioner George P. Bush attends a 2016 Veterans Day celebration. He's running for reelection with President Trump's endorsement, two years after his father's presidential bid failed amid withering insults from Trump. LM Otero/AP hide caption
Voters stand in line to cast their ballots inside Calvary Baptist Church March 1, 2016, in Rosenberg, Texas. Erich Schlegel/Getty Images hide caption
Mississippi state Sen. Chris McDaniel is expected to make his primary challenge against incumbent Republican Sen. Roger Wicker official on Wednesday. Rogelio V. Solis/AP hide caption
The United States Capitol building in Washington, D.C. Getty Images hide caption
Russian President Vladimir Putin delivers a speech in Moscow's Red Square last May. Russian-backed efforts attempting to interfere in U.S. politics appear to be evolving. Yuri Kochetkov/AFP/Getty Images hide caption
Tracking Shows Russian Meddling Efforts Evolving Ahead Of 2018 Midterms
Tea Party activists hold a rally on Capitol Hill in 2010. That grassroots movement, with backing from the Koch political network, helped Republicans win back the House in the 2010 midterms. In 2018, the Koch network is on defense against Democratic gains. Chip Somodevilla/Getty Images hide caption
Koch Brothers, Behind Tea Party Wave, Face Democrats' Rising Tide In 2018
Steve Bannon, the former chief strategist to President Trump, speaks in Warren, Mich., in November. Two months later, he was shunned by the president and out of a job at Breitbart News. Paul Sancya/AP hide caption
Representative Darrell Issa, R-Calif., became the 31st Republican to announce he is not seeking re-election in this year's midterms. Bloomberg/Bloomberg via Getty Images hide caption
Senator-elect Doug Jones, D-Ala., speaks to the press last week after his win in the Alabama special election. Mark Wallheiser/Getty Images hide caption
Virginia Gov.-elect Ralph Northam (right) and Lt. Gov.-elect Justin Fairfax greet supporters at an election night rally Tuesday after the Democrats' victory. Win McNamee/Getty Images hide caption
Sen. Bob Corker, R-Tenn. (center), talks to reporters on Capitol Hill. He decided Tuesday not to seek a third term. Corker is the first Senate retirement of the 2018 election cycle. Jacquelyn Martin/AP hide caption
Democratic congressional candidate Jared Golden making his announcement speech last month in Maine. Steve Mistler/Maine Public Radio hide caption