(CNN) - As evidence of a tightening presidential race mounts, CNN is altering its Electoral Map, shifting Minnesota and its ten electoral votes from leaning towards Barack Obama to a toss up state.
With the shift of Minnesota, CNN now estimates that if the presidential election were held today, Obama would win 233 electoral votes and John McCain 189. There are 116 electoral votes up for grabs; 270 electoral votes are needed to win the White House.
A CNN/Time Magazine/Opinion Research Corporation poll conducted two weeks ago had Obama up 12 points over McCain in Minnesota. But a Minneapolis-St.Paul Star Tribune poll released Sunday suggests the race is tied, with each candidate getting the support of 45 percent of Minnesota voters questioned in the survey. The poll was conducted entirely after the end of the Republican National Convention, which was held in St. Paul, Minnesota.
"Events are moving so quickly in the presidential race that polls taken before the Republican convention probably aren't accurate reflections of what is going on in swing states today," said CNN Polling Director Keating Holland. "The pace of the campaign means that we may see more shifts, in either direction, in states like Minnesota."
The CNN Electoral Map takes into account a number of factors, including the most recent state polls, voting trends, and campaign ad spending and events in the particular states.