Kerry didn't mention names or parties, but in an emotional speech suggested some lawmakers have put their own interests ahead of the national interest, The Boston Globe reported. Gridlock threatens the U.S. reputation abroad and erodes relationship-building and bipartisan cooperation in the Senate, Kerry said.
The Senate overwhelmingly approved Kerry's nomination Tuesday.
"As I prepare to represent our nation in capitals around the world," Kerry said in prepared remarks, "I'm conscious that my credibility as a diplomat -- and ours as a country -- is determined to a great degree by what happens in our own capital city. We can be no stronger abroad than we are at home.
"If we posture politically in Washington, we weaken our position across the world. If democracy deadlocks here, we raise doubts about democracy everywhere. If we do not in our deeds prove our own ideals, we undermine our security and our sacred mission as the best hope of Earth."
Kerry said the nation's problems "come from individual choices made by senators themselves not the rules."
"When an individual senator -- or a colluding caucus -- determines the comity essential to an institution like the Senate is a barrier to individual ambition or party ambition, the country loses," he said. "Those are the moments in which the Senate fulfills, not its responsibility to the people, but its reputation as a sanctuary of gridlock."
Kerry said a "dangerous but reversible" erosion in the quality of U.S. democracy is caused by "the decline of comity, the deluge of money, and the disregard for facts."
Kerry, who was elected in 1984, paid tribute to colleagues, and the late Sen. Edward Kennedy, who died in 2009.