BOWLING GREEN, Ky.—Tea-party leaders, cheering as some of their movement's most prominent figures won U.S. Senate seats in Kentucky and Florida, said Tuesday's elections were only the beginning of their quest to transform government.

"Things look good for tonight," said Jenny Beth Martin, national coordinator of the Tea Party Patriots, an umbrella group that says it has 2,800 local affiliates around the country. "No one in this movement is stopping today. This is not an endgame. This is just a beginning."

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