[img_assist|nid=2342|title=Barack Obama|desc=Getty Images Photo |link=none|align=left|width=175|height=249]Democratic presidential nominee Barack Obama has a four-point lead over Republican opponent John McCain in Colorado, according to a Suffolk University poll released Tuesday.

The poll also showed Democratic U.S. Senate nominee Mark Udall with an 11-point lead over Republican Bob Schaffer

But despite Obama's lead in the poll, as the margin of error is +/- 4 percent, the presidential race in Colorado may well be in a dead heat.

"Despite a small Obama lead, Colorado is up for grabs," said David Paleologos, director of the Political Research Center at Suffolk University, in a statement. "When the history of this election is written,one common thread will be how voters have repeatedly up-ended the conventional wisdom."

The survey was conducted Oct. 10-13 among 600 likely voters.

Obama crucially held a 20-point lead among Colorado independent voters in the poll.

Coloradans who were optimistic about the American economy favored Republican John McCain 49 percent to 47 percent. Those who said they were pessimistic favored Obama 48 percent to 37 percent.

"If McCain can convince Colorado independents that there is bi-partisan hope at the end of the economic tunnel, he will close the overall margin in the state," Paleologos said in the statement. "If Obama makes the presidential election a referendum on the current state of the economy, he will extend his lead."

Independent Ralph Nader polled 2 percent in the survey; Libertarian Party nominee Bob Barr polled 1 percent. Six percent of voters surveyed were undecided.

In the "bellwether" of Alamosa County, a separate poll of 300 likely voters showed Obama leading McCain 45 percent to 43 percent.

In 2008, Suffolk University "bellwethers" were 95 percent accurate in predicting winners in both Democratic and Republican primaries, and were 100 percent accurate in predicting winners when coupled with the results of the statewide poll, according to a press release.

CORRECTION: An earlier version of this article stated, in error, that the Alamosa County poll was part of the statewide poll. It was a separate poll conducted by Suffolk University.