When Republican-turned-Democrat Charlie Crist threw his hat into the ring for the 2014 Florida governor's race, it appeared as if the former governor had a good shot at getting his job back. He may have raised some eyebrows by switching parties, but Crist was still much more popular than Florida's Republican Gov. Rick Scott.

Then, Scott and his allies unleashed a slew of negative advertising. For months, Florida voters have heard that Crist is a "slick politician" but a "lousy governor." They've heard that "Charlie Crist is for Barack Obama" -- not the people of Florida

Since March, Scott and his GOP allies have spent around $44 million on advertising, the Miami Herald reported this week, while Crist and his allies have spent a relatively paltry $19.7 million.

Get Breaking News Delivered to Your Inbox

The steady drumbeat of attack ads has dragged Crist's approval rating down.

"The governor had to cut him down to size, so he did," longtime Republican consultant John Stipanovich told CBS News.

The Crist campaign has managed to keep Scott unpopular, calling the governor a "fraud" who's "too shady for the Sunshine State."

Now polls show the race is as close as ever.

With the governor's mansion up for grabs in a state that's crucial in presidential politics, both Crist and Scott are seeing some high-profile support in the final weeks of their campaign. On Wednesday, New Jersey Gov. Chris Christie -- chairman of the Republican Governors Association and a potential 2016 presidential candidate -- will appear with Scott at two campaign events.

These final weeks of campaigning and advertising in Florida are crucial, given that some voters are already turning in absentee ballots. Additionally, in some counties, early voting starts on Oct. 20, two weeks before Election Day.

That may explain the final barrage of ads that Florida voters have endured in recent weeks. According to the Wesleyan Media Project, more than 20,000 ads for the Florida governor's race ran from Sept. 12-25. That's nearly twice the number of ads that ran in Texas, which had the second heaviest volume of gubernatorial campaign ads during that time period. It's also far more than the number of ads that ran in any single race for the U.S. Senate during that period.

Furthermore, the Wesleyan Media Project noted that more than 68 percent of those ads were negative, while just about 26 percent were positive and 6 percent were "contrast ads." Only Maryland and Illinois had higher percentages of negative ads during that time period.

The content of the negative ads isn't that remarkable, Floridians say, but the sheer number of negative ads is noteworthy.

"It is more negative than average, but not groundbreaking by any stretch of the imagination," said Stipanovich. "What's unusual about it is not necessarily the level of vitriol but the almost total absence of any counterbalancing or ameliorating messaging -- there are no positive messages. I've seen a commercial of the governor and [his wife] Ann walking on the beach and talking about being high school sweethearts, but that's about it."

The polling shows the damage that the ads have done.

A Quinnipiac poll released late last month showed Scott winning 44 percent of support from likely voters and Crist winning 42 percent, making the race too close to call. Libertarian candidate Adrian Wyllie won 8 percent support. Other polls with more questionable methodologies have also shown very close races with Wyllie winning a small but noteworthy portion of voters.

Just 41 percent of likely voters in the Quinnipiac poll said they had a favorable view of Crist, while just 42 percent said they had a favorable view of Scott. As the Miami Herald notes, Scott's favorability rating has always been relatively poor, but Crist's has sunk 25 points from last summer.

"When fewer than four in 10 voters think both the Democratic and Republican candidates for governor are honest, you know this has been one of the nastiest races in state history," Peter A. Brown, assistant director of the Quinnipiac University Poll, said in a statement. "They have been throwing so much mud that they both are covered in it."

One of Scott's most recent ads actually attacks Crist for running negative ads.

"After all these attack ads, Charlie Crist wants you to hate me," Scott says in the spot. "I guess that's all he's got."

Steve Vancore, a Democratic consultant and pollster in Florida, told CBS News that going negative is probably the right move for Crist. Evidence shows that voters "are more likely to believe negative messages about the other guy than positive messages about yourself," he said.

At this point, the race is largely about turnout, Vancore and Stipanovich said.

"You have to understand that in Florida, there will be more Republicans voting than Democrats, period," Vancore said.

In Florida's 2010 and 2006 races, Republican turnout was higher than Democratic turnout, even though the number of registered Democrats in the state outnumber registered Republicans by about 3.8 percent.

Consequently, Crist has focused on building a strong presence in Broward County, where he can work on mobilizing Democratic voters.

Crist and Scott are also counting on a little star power from the likes of New Jersey Gov. Christie and former Secretary of State Hillary Clinton to secure fundraising. Last week, Clinton helped Crist raise $1 million at a private fundraiser last week.