Hours before President Barack Obama campaigns in Boulder, Colo., a new survey indicates a very close contest between the president and Republican nominee Mitt Romney for the Centennial State's nine electoral votes.

According to a CNN/ORC International poll, 50% of likely voters in Colorado support Obama, with 48% backing the former Massachusetts governor. The president's two-point margin is well within the survey's sampling error.

The poll's Thursday release also came just two hours after Rep. Paul Ryan, the GOP running mate, headlined a rally in Greeley, Colorado. The top line results of the CNN survey are very similar to an American Research Group poll conducted this past weekend which had Romney at 48% and Obama at 47%, and an NBC News/Wall Street Journal/Marist poll conducted last week which suggested the race was tied up at 48%.

"If you didn't know why President Obama and Paul Ryan are here today, and Mitt Romney is coming Saturday, now you know," said CNN Chief National Correspondent John King, who was reporting Thursday from Colorado.

As in most swing states, there is a fairly big gender gap, with the CNN poll indicating Romney ahead among men by 10 points and Obama winning women by 13 points. Income is also an important indicator, with the president holding a big lead among lower-income voters, while voters with more than $50,000 in income last year are tied at 49% for Romney and 49% for Obama.

"But the key may be the split between the Denver area and the rest of Colorado, with the suburbs throughout the state likely to determine the winner," said CNN Polling Director Keating Holland.

According to the survey, Obama beats Romney by nearly two to one in the two big urban Democratic strongholds of Denver and Boulder. In the Denver suburbs (Adams, Arapahoe, Jefferson and Broomfield counties), Obama's support drops but he still holds a 53%-45% margin over Romney.

"But the GOP challenger appears to do better in many Front Range suburbs around cities like Fort Collins and Colorado Springs. Combine those Front Range communities with the rural east and west and Romney has a 55%-43% lead once you get beyond the greater Denver area," said Holland.

In the battle for crucial independent voters, the poll indicates the president has a 49%-47% edge.

"The president's strength in Denver and Boulder suggests Governor Romney is going to need strong evangelical and rural turnout. Splitting the votes of self described independents probably isn't good enough for the governor. He needs to boost that number in the final days to win," added King. "And while our poll gives the president a tiny edge, it's also proof his ground operation must deliver in the cities and closest suburbs."

Could minor-party candidates act as spoilers in Colorado?

It's tough to tell, but it is intriguing to note that when three minor party candidates are included in a separate horse race question, a 50%-48% advantage for Obama becomes a 48%-47% margin, with Libertarian Gary Johnson pulling 4% and Green party candidate Jill Stein claiming one percent, and Constitution Party candidate Virgil Goode coming in with less than one-half of one percent. Statistically, there is no difference between 50%-48% and 48%-47%, but it does illustrate the potential effect of the minor-party candidates in this extremely close race.

Ninety-four percent of people questioned said they've made up their minds on their pick, with 5% saying they could still change their minds.

"As always, keep in mind that the poll does not, and cannot, predict the outcome of the election," cautions Holland. "Close elections are inherently unpredictable -- and elections in which a couple of percentage points separate the two candidates are even tougher, if not impossible, to forecast."

President George W. Bush carried Colorado by five points in his 2004 re-election. Four years later then-Sen. Obama accepted his party's presidential nomination at the Democratic convention in Denver, and he won the state by nine points over Sen. John McCain in the 2008 election.

This cycle both candidates as well as their running mates and surrogates have made numerous trips to Colorado since the start of the general election in early April.

The two presidential campaigns, the party committees, and the super PACs and other independent groups backing the two candidates combined have spent over $60 million to run ads on broadcast TV in Colorado since the start of the general election in early April, according to Campaign Media Analysis Group (CMAG), which tracks ad spending for its clients. Just in the past week, $6 million has been shelled out to run spots.

The CNN poll was conducted by ORC International, October 26-31 (entirely after the third and final presidential debate), with 984 adults, including 904 registered voters and 733 likely voters, questioned by telephone. The survey's sampling error for likely voters is plus or minus 3.5 percentage points.