Security has been beefed up around some potential 2020 Democratic presidential candidates, and concerns about the mail bombs addressed to former President Barack Obama, former presidential nominee Hillary Clinton and former Vice President Joe Biden have risen to the top of pre-November debates in races across the country.

The investigation into the mail bombs comes as Democrats are seeking to pick up a net of 23 seats to win back control of the House and Republicans are defending a narrow 51-49 Senate majority.

A look at midterm campaign activities Thursday:

Biden speech

Senator Bill Nelson speaks to students attending a Vote Early, Vote Loud Rally at Florida International University, Thursday, Oct. 25, 2018 in Miami. (Emily Michot /Miami Herald via AP)

The University at Buffalo said it was “implementing significant security measures” for a Thursday night speech featuring former Vice President Joe Biden and “taking extra precautions because of recent targeting of political figures.” About 6,500 people were expected at the Biden speech, and a university spokesman said Alumni Arena would be subjected to a security sweep before ticketed patrons arrive. All attendees will be required to pass through metal detectors, and coats and large bags will be searched.

Two packages addressed to Biden were seized by authorities in Delaware early Thursday, suggesting a broad pattern to target prominent Democrats. The former vice president, a potential 2020 presidential candidate, has been traveling widely in recent weeks in support of Democrats running in the midterms.

Avenatti interview

A published report quotes Los Angeles attorney Michael Avenatti, who represents porn actress Stormy Daniels, as saying the 2020 Democratic presidential nominee should be a white male. Avenatti says he was misquoted.

Avenatti, a prominent Trump critic, was quoted by Time as saying that when it comes to the party’s 2020 nominee, “I think it better be a white male.” He told the news magazine that he wishes it weren’t so but that people listen to white men more than they listen to other people.

“When you have a white male making the arguments, they carry more weight,” Avenatti said, according to Time. “Should they carry more weight? Absolutely not. But do they? Yes.”

Asked about the comments, Avenatti told The Associated Press, “I was misquoted and I was taken out of context.” He declined to elaborate.

Time said it stands by its reporting and later released a transcript showing he made the statements.

Avenatti tweeted that he has “consistently called on white males like me to … take responsibility” and help stop “the sexism and bigotry that other white males engage in.”

Avenatti said earlier Thursday that he had increased his security measures since the mail bombs started popping up and that his mail was being screened offsite.

Missouri Senate

A Senate debate in Missouri on Thursday focused on a vitriolic political climate across the nation and finger-pointing between the two major parties.

Republican candidate Josh Hawley accused Democrats of inserting incivility in politics while Democratic Sen. Claire McCaskill said both sides need to “turn down the temperature” and said Hawley’s blame was misplaced.

Hawley, in the debate hosted by KMBC-TV in Kansas City, cited “mobs popping up” after confirmation hearings for Supreme Court Justice Brett Kavanaugh. He also referenced former Attorney General Eric Holder’s comment that when those on the opposite side of the aisle “go low,” Democrats should “kick ’em.”

McCaskill criticized Hawley for not acknowledging the role of Trump’s “incendiary” rhetoric.

Mississippi debates

A Republican appointed to the Senate representing Mississippi expressed a willingness to debate a Democratic challenger if the race reaches a runoff in a special election.

Mississippi Sen. Cindy Hyde-Smith told The Greenwood Commonwealth that she thinks Mike Espy “would be very civil.”

Hyde-Smith was appointed to temporarily succeed Republican Sen. Thad Cochran, who resigned in April.

Hyde-Smith has declined to debate all three challengers before the Nov. 6 special election, which includes Espy, a former agriculture secretary under President Bill Clinton; Chris McDaniel, a Republican state senator; and Tobey Bernard Bartee, a Democrat who is a former military intelligence officer.

If no candidate wins a majority, the top two will advance to a Nov. 27 runoff. The winner will serve the final two years of Cochran’s six-year term.

Gillibrand pledge

New York Sen. Kirsten Gillibrand, considered a potential Democratic candidate for the White House in 2020, said during a Thursday debate with her Republican challenger that she will serve out her six-year Senate term if she’s re-elected next month.

Gillibrand, whose star has risen quickly since she succeeded Hillary Clinton in the Senate in 2009, also fielded questions about immigration, health care and other issues during a half-hour televised debate held in WABC-TV’s studio in Manhattan.

When asked her plans in two years, Gillibrand responded: “I will serve my six-year term.”

Opponent Chele Farley, who works in the financial services industry, scoffed at the answer. “Honestly, I don’t believe that, considering this is the third day that she has been in New York during the month of October when she has been in five other states including New Hampshire this month,” Farley said.

Gillibrand campaigned last week in New Hampshire, the home of the nation’s first presidential primary, on behalf of Molly Kelly, a Democrat who is running for governor.

Florida debate

In Florida’s gubernatorial debate on Wednesday night, Republican former Rep. Ron DeSantis and Democratic Tallahassee Mayor Andrew Gillum were asked about the bombs sent to Democratic leaders. DeSantis condemned the actions, noting that he was at the 2017 congressional baseball practice in which Rep. Steve Scalise, R-La., was wounded by a gunman whose social media posts had suggested he targeted Republicans.

“I know firsthand that when we start going down that road, that can be very, very deadly,” DeSantis said.

Gillum said he was grateful that no one had been hurt. “But,” he said, “we’ve really seen a collapsing of our political discourse.”