Hartford, Conn. ? Democratic Sen. Joe Lieberman, locked in a battle to keep his Senate seat against an anti-war challenger, said on the eve of today’s primary that the voters who were upset with him were trying to “send me a message,” and he assured them: “I got their message.”

In Georgia, Rep. Cynthia McKinney, who made headlines this year for a scuffle with a U.S. Capitol Police officer, faced a runoff for her district’s Democratic nomination.

Primaries are also being held today in Colorado, Missouri and Michigan.

Lieberman’s seat was the biggest prize at stake. If defeated, he would be only the fourth incumbent senator since 1980 to lose a primary election.

The three-term senator, nationally known for his centrist views, has endured harsh criticism in his home state for supporting the Iraq war and has been labeled by some Democrats as too close to Republicans and President Bush.

Lieberman has campaigned with the support of party leaders in Washington and at home. But a defeat would strip him of that backing as early as tonight or Wednesday, and he likely would come under pressure from longtime allies to abandon plans to run as an independent this fall.

Challenger Ned Lamont, a millionaire owner of a cable television company, held a slight lead of 51 percent to 45 percent over Lieberman among likely Democratic voters heading into today’s primary. The race has tightened in recent days, with Lamont’s lead cut from 13 points.

In Georgia, McKinney is trying to counter her opponent’s charge that the six-term congresswoman is “the candidate of polarization and divisiveness.”

McKinney, the state’s first black woman in Congress, once claimed the Bush administration had advance knowledge of the 9-11 terror attacks. In March, she struck a Capitol Police officer who did not recognize her and tried to stop McKinney from entering a House office building.

A grand jury in Washington declined to indict her, but she was forced to apologize in the full House. She drew less than 50 percent of the vote in last month’s primary and faces off against Hank Johnson, the black former commissioner of DeKalb County, which encompasses much of Atlanta.

In other primaries today:

¢ Missouri Republican Sen. Jim Talent and Democratic challenger Claire McCaskill, the state auditor, are expected to win their party’s primaries. Voters will also decide whether to renew a 22-year-old sales tax to fund state parks and other conservation initiatives.

¢ In Colorado’s heavily conservative 5th District, voters will choose among six GOP candidates to succeed retiring Republican Rep. Joel Hefley, a 10-year veteran. The winner will face Democratic Air Force veteran Jay Fawcett. In another race, three Democrats are competing to replace U.S. Rep. Bob Beauprez, the Republican nominee for governor.

¢ In Michigan, Republican Rep. Joe Schwarz faces a serious challenge from former state lawmaker Tim Walberg. Schwarz, a moderate Republican, is backed by President Bush and Sen. John McCain.