Cowan sworn in as interim Massachusetts senator

Cowan, flanked by Sen. Elizabeth WarrenElizabeth WarrenTrump was wrong: Kaine is a liberal in a moderate's clothing Progressive groups urge Clinton to lead fight against a TPP vote Amazon hires antitrust lobbyist MORE (D-Mass.) Kerry, was sworn in by Vice President Biden. He is now the Senate's second black senator, and the only black Democratic senator.

He will serve until a special election to replace Kerry occurs in June. Democrats are likely to retain the seat, as Massachusetts Republicans have been unable to front a strong challenger since former Sen. Scott Brown (R-Mass.) decided against a run.

Reps. Edward MarkeyEd Markey'Power problem' grounds southern Florida flights Dem senator criticizes Facebook, Instagram for gun sales Apple, Google enlisted for FCC robocall effort MORE and Stephen Lynch have both announced their intentions to pursue the Democratic nomination for the seat, and face a primary on April 30.

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