By Jason Lange
WASHINGTON (Reuters) - Republican Senator Thom Tillis of North Carolina is statistically even with Democratic challenger Cal Cunningham, while Democratic Senator Gary Peters of Michigan leads Republican John James, a Reuters/Ipsos poll showed on Tuesday.
There are about 12 competitive U.S. Senate races up for grabs in the Nov. 3 election, 10 with vulnerable Republican incumbents and two with vulnerable Democrats. To have a majority in the Senate, Democrats need to pick up three seats if the party wins the White House, which gives the vice president a tie-breaking vote, and four if not.
Here are the latest results for three Senate races on which Reuters/Ipsos is polling:
NORTH CAROLINA (Oct. 21-27 poll)
* Voting for Democratic challenger Cal Cunningham: 48%
* Voting for Republican Senator Thom Tillis: 47%
* The race is statistically tied because the difference between the two is within the survey's credibility interval, as it was the prior week when Cunningham and Tillis were even at 47%-47%.
* 35% said they had already voted.
MICHIGAN (Oct. 21-27 poll)
* Voting for Democratic Senator Gary Peters: 50%
* Voting for Republican challenger John James: 44%
* Peters led James 50%-45% in the prior week.
* 32% said they had already voted.
ARIZONA (Oct. 14-21 poll)
* Voting for Democratic challenger and former astronaut Mark Kelly: 51%
* Voting for Republican Senator Martha McSally: 44%
* Kelly was up 52%-41% in the prior poll.
* 27% said they had already voted.
NOTES: The Reuters/Ipsos poll was conducted online and in English. The Michigan poll surveyed 652 likely voters and had a credibility interval of 4 percentage points. North Carolina's surveyed 647 likely voters and had a credibility interval of 4 percentage points. The earlier Arizona survey included 658 likely voters and had a credibility interval of 4 percentage points.