Democrats must gain six seats in Tuesday's election to win US Senate control, and they lead in six of the seven most vulnerable Republican-held states, according to Reuters/Zogby polls released on Thursday.
Democrats lead Republican incumbents in Pennsylvania, Ohio, Missouri, Montana, Virginia and Rhode Island, but only the Rhode Island and Pennsylvania races are outside the poll's margin of error of plus or minus 4 percentage points. The polls of at least 600 likely voters in each state, taken October 24 to October 30, have a margin of error of plus or minus 4 percentage points.
Here is a summary of the results in each race polled:
CONNECTICUT: Senator Joseph Lieberman, running as an independent, has a 49 percent to 37 percent lead on Democratic anti-war challenger Ned Lamont, down from a 20-point lead in early October. Lieberman, a three-term Democratic incumbent, lost the party primary in August after Lamont attacked his support for the Iraq war.
MARYLAND: Democratic Representative Ben Cardin leads Republican Lieutenant Governor Michael Steele by 49 percent to 44 percent in the race to replace retiring Democratic Senator Paul Sarbanes. Cardin led by 8 points in early October.
MISSOURI: Democratic state Auditor Claire McCaskill took a 46 percent to 43 percent lead over Republican Senator Jim Talent, who had a 4-point lead in early October. The see-sawing contest has been close all year, with neither candidate opening a significant advantage.
MONTANA: Democrat Jon Tester holds a 47 percent to 46 percent lead over fast-closing Republican Senator Conrad Burns, down from a 4-point lead in early October. Burns is fighting back from a series of problems, including links to convicted lobbyist Jack Abramoff and comments seen as insensitive to some ethnic groups.
NEW JERSEY: Democratic Senator Robert Menendez, considered vulnerable after polls showed a tightening race, leads Republican challenger Tom Kean by 49 percent to 37 percent. That is up slightly from his 10-point lead in early October.
OHIO: Democratic Representative Sherrod Brown leads Republican Senator Mike DeWine by 49 percent to 42 percent. The two were in a dead heat at 41 percent in early October.
PENNSYLVANIA: Democrat Bob Casey, the son of a popular former governor, leads third-ranking Senate Republican Rick Santorum by 48 percent to 40 percent. Casey led by 12 points in early October.
RHODE ISLAND: Senator Lincoln Chafee, a moderate Republican in one of the most Democratic states, trails Democratic challenger Sheldon Whitehouse by 53 percent to 39 percent. Whitehouse led by 4 points in early October.
TENNESSEE: In a bitter race for the open seat of retiring Senate Republican Leader Bill Frist, Republican Bob Corker, the former mayor of Chattanooga, opened up a 53 percent to 43 percent lead on Democratic Representative Harold Ford. The two were tied in early October.
VIRGINIA: Democratic challenger James Webb holds a slim 45 percent to 44 percent lead over Republican Senator George Allen, who led by 11 points in the last survey. Allen has suffered a series of campaign missteps.