(CNN) -- If the polls are a reliable predictor, Chris Coons has the Delaware Senate race wrapped up.
But a lot can change between now and Election Day.
Just ask Rep. Mike Castle, who had been considered a shoo-in to be Delaware's next U.S. senator before he was upset by Tea Party-backed Christine O'Donnell in the GOP primary.
Polls showed that if Castle had won his party's nomination, he would be leading Coons by almost 20 points in the general election race.
Coons, the executive of New Castle County, holds a 19-point lead over O'Donnell, according to a Monmouth University Poll released Tuesday. Among likely voters, 57 percent said they will vote for Coons; only 38 percent said they support O'Donnell.
And when it comes to who is qualified, 64 percent said Coons is qualified to be a senator while only 35 percent said O'Donnell is, the poll found.
Last week, a Fairleigh Dickinson University PublicMind survey indicated 53 percent of likely voters in Delaware supported Coons; 36 percent backed O'Donnell, the Tea Party favorite.
According to a University of Delaware Center for Political Communication survey also released last week, 49 percent of Delaware registered voters questioned support Coons, with three in 10 backing O'Donnell and 13 percent undecided.
But David Wilson, the professor who conducted the poll, said O'Donnell still has time to catch up: "There's an awful lot of 'don't know' or undecided voters still, and this is across all three counties."
A new ad, paid for by the Friends of Christine O'Donnell, is a spoof movie trailer that attacks Coons record on taxes. The ad, titled "Coons the Taxman," says "Hide your will. Hide your lights. 'Cause he's taxing everything out here."
For the most part, Coons' campaign has been on offense -- attacking O'Donnell not only on substance, but also on the candidate's sometimes bizarre comments.
In a 1999 television interview, she said she once "dabbled into witchcraft." That comment, among other things, drew scorn from Coons, Democrats and even Republicans. Still, many Republicans, such as Sarah Palin, have stood by her.
Despite O'Donnell's missteps, Coons points out that she has raised huge sums of money since her primary win.
"I take her seriously. She is the Republican Party nominee. She's my opponent. If you believe her website, she's raised $2.8 million over the internet in the last three weeks."
Coons has had his own troubles when it comes to past statements: He called himself a "bearded Marxist" in a college newspaper article. But in an interview that aired on "John King, USA," Coons said the article was meant to be "tongue-in-cheek."
"I am not now, nor have I ever been, a Marxist or an enemy of the people of the United States," Coons said. "What really matters is not what was said in some student newspaper or what was said in some interview 10 or 20 years ago."
Observers are give Coons the edge in this closely watched race.
Nonpartisan analysts Charlie Cook and Stu Rothenberg flipped their projections for Delaware from "lean Republican" to "lean Democratic" after O'Donnell's primary win in September.
The race to fill Vice President Joe Biden's old U.S. Senate seat has been in the national spotlight since O'Donnell beat Castle in the primary.
Coons' Democratic primary was much less contentious. Early on, state Democrats lined up behind the vice president's son, Delaware Attorney General Beau Biden. But Biden decided not to run, as did other Democrats.
Since becoming the nominee, Coons has received an outpouring of support from Joe Biden, who has repeatedly campaigned for him. President Obama and the vice president travel Friday to Delaware to campaign for Coons.
While Coons, 47, is running his first statewide campaign, he's neither a political novice nor a party outsider. In 1988, Coons served as a policy researcher for the failed Senate campaign of then-Lt. Gov. S.B. Woo.
He went on to earn a degree from Yale Law School, as well as a master's in ethics from Yale Divinity School.
Coons later clerked for Judge Jane Richards Roth on the U.S. 3rd Circuit Court of Appeals and worked as an attorney for W.L. Gore & Associates, the manufacturerer of Gore-Tex.
Before his election to the New Castle County Council in 2000, Coons also worked for Delaware's "I Have a Dream" Foundation, which provides educational assistance for low-income children. He is still on the foundation's board of directors, according to its website.
In 2004, Coons was elected executive of New Castle County, which includes Wilmington and Newark.
CNN's Gabriella Schwarz, Alan Silverleib and Paul Steinhauser contributed to this report.