Among the charges: a 10-year, interest-bearing $46,000 loan that he and his wife made to a top aide in the U.S. attorney's office in need of financial help that he neglected to report on his tax filings or financial-disclosure forms.
At a recent news conference, Christie apologized for failing to report the loan and said he had amended his tax filings. "When I make mistakes, I'm going to admit them. It was certainly nothing that I was trying to conceal or hide," he said.
But these and other charges have apparently cut into his lead, though Corzine's approval numbers remain in the basement. A Rasmussen poll last week showed Christie ahead with an eight-point lead, 50 percent to 42 percent, with 7 percent "not sure."
Even so, Corzine's job-approval numbers are very weak: 35 percent approve, while 65 percent disapprove.
"There is a natural tightening occurring. We've long expected it would. New Jersey is an overwhelmingly Democratic state, so we never expected a 14-point lead to hold," said Nick Ayers, executive director of the Republican Governors Association.
"It can be attributed to a variety of factors. Some to the fact that Corzine is slinging mud, some to the fact that the base of Democrats is solidifying toward Corzine, but mostly as Election Day nears, polls tend to tighten," he told me.
New Jersey's voters, who will go to the polls this November, have not elected a Republican to statewide office since 1997, and, though they may be turning against Corzine now, past elections often show that Democratic candidates tend to move into the lead in the race's closing weeks.
There is another big factor that works in the Democrats' favor. Corzine, a multimillionaire who made a fortune on Wall Street as a chief executive with Goldman Sachs, is self-financing his campaign and will easily spend $30 million to $40 million on his race. Christie, however, is abiding by state public financing and will have a total of $11.5 million to spend.
But maybe New Jersey voters have had enough of one-party rule and a state political machine that is one of the most corrupt in the country.
Republicans are optimistic that this time things are going to be different.
"Corzine can spend $40 million distorting Chris Christie's record, but what he can't change is his record over the past four years," Ayers said.
"Is corruption a big problem? Wow, is it," said Maurice Carroll, director of the Quinnipiac University Polling Institute. "Almost everyone in New Jersey thinks so. And two-thirds feel personally embarrassed to live in a state where politicians are pictured in handcuffs."