United States presidential election

FILE - In this April 10, 2019, file photo, outgoing Homeland Security Secretary Kirstjen Nielsen speaks at the dedication ceremony at the Homeland Security headquarters Center Building at the old St. Elizabeths Hospital in Washington. Nielsen was told by President Donald Trump’s chief of staff not to bring up election security in meetings with the president, but she continued to push the issue with administration and international leaders despite the lack of White House coordination. That’s according to people familiar with the matter. Nielsen, who resigned in April, had made cybersecurity a focus of her tenure there. (AP Photo/Alex Brandon, File)

FILE - In this Sept. 27, 2018, file photo, White House counsel Don McGahn listens as Supreme court nominee Brett Kavanaugh testifies before the Senate Judiciary Committee on Capitol Hill in Washington. Rep. Jerrold Nadler, the chairman of the House Judiciary Committee has subpoenaed McGahn for testimony following the release of the report from special counsel Robert Mueller. (Saul Loeb/Pool Photo via AP, File)

FILE - In this Sept. 27, 2018, file photo, White House counsel Don McGahn listens as Supreme court nominee Brett Kavanaugh testifies before the Senate Judiciary Committee on Capitol Hill in Washington. Rep. Jerrold Nadler, the chairman of the House Judiciary Committee has subpoenaed McGahn for testimony following the release of the report from special counsel Robert Mueller. (Saul Loeb/Pool Photo via AP, File)

FILE - In this Oct. 4, 2018 file photo, the U.S. Supreme Court is seen at sunset in Washington. The Supreme Court will decide whether the main federal civil rights law that prohibits employment discrimination applies to LGBT people. The justices say Monday they will hear cases involving people who claim they were fired because of their sexual orientation. (AP Photo/Manuel Balce Ceneta)

FILE - In this June 20, 2014 file photo, Herman Cain, CEO, The New Voice, speaks during Faith and Freedom Coalition's Road to Majority event in Washington. Trump says Herman Cain withdraws from consideration for Fed seat amid focus on past allegations. (AP Photo/Molly Riley, File)

Ukrainian comedian and presidential candidate Volodymyr Zelenski speaks to his supporters at his headquarters after the second round of presidential elections in Kiev, Ukraine, Sunday, April 21, 2019. Ukrainians voted on Sunday in a presidential runoff as the nation's incumbent leader struggles to fend off a strong challenge by a comedian who denounces corruption and plays the role of president in a TV sitcom. (AP Photo/Vadim Ghirda)

FILE - In this Aug. 1, 2018, file photo, Rudy Giuliani, an attorney for President Donald Trump, speaks in Portsmouth, N.H. President Donald Trump's lawyers are putting the finishing touches on a rebuttal to the forthcoming report by special counsel Robert Mueller. Giuliani, one of the president's attorneys, said Tuesday, April 16, 2019, that their document will be dozens of pages long. (AP Photo/Charles Krupa, File)

U.S. Rep. Jerrold Nadler, D-N.Y., chair of the House Judiciary Committee, speaks during a news conference, Thursday, April 18, 2019, in New York. (AP Photo/Mary Altaffer)

Marine One with President Donald Trump aboard, departs the South Lawn of the White House, Thursday, April 18, 2019, for a short trip to Andrews Air Force Base, Md. President Trump is traveling to his Mar-a-lago estate to spend the Easter weekend in Palm Beach, Fla. (AP Photo/Andrew Harnik)

President Donald Trump waves during his arrival with first lady Melania Trump on Air Force One at Palm Beach International Airport, Thursday, April 18, 2019, in West Palm Beach, Fla. Trump traveled to Florida to spend the Easter weekend as his Mar-a-Lago estate. (AP Photo/Pablo Martinez Monsivais)