Kennedy is the widow of Sen. Edward M. Kennedy (D-Mass.). McCain is the widow of Sen. John McCain (R-Ariz.).
Tuesday’s votes came as Sen. Ted Cruz (R-Tex.) has threatened to delay the confirmations of dozens of State Department nominees and other national security picks in an ongoing battle with the White House over its foreign policy agenda.
Before Tuesday, just one of Biden’s choices to be a U.S. ambassador in a foreign capital — former interior secretary and senator Ken Salazar (D), confirmed in August as ambassador to Mexico — had been approved by the Senate.
That means Biden is lagging considerably behind his immediate predecessor, Donald Trump, who at this point in his presidency had 22 U.S. ambassadors confirmed.
The four nominees confirmed Tuesday were among a group of nearly three-dozen approved by the Senate Foreign Relations Committee this month. It remains unclear when the other nominees may see a Senate floor vote.
Cindy McCain, too, backed Biden in 2020 and has been critical of Trump, who frequently attacked her late husband on Twitter and in campaign speeches.
Biden went on to become the first Democratic presidential nominee to win Arizona since Bill Clinton in 1996. The state also has two Democratic senators, Kyrsten Sinema and Mark Kelly.
Seung Min Kim contributed to this report.