The senator is not an exorbitantly wealthy man, and devoting significant time and money to a legal fight could be draining—both financially and politically. Menendez is up for election in 2018, and there's no telling whether the potential case against him will be resolved by then.
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"It's really impossible to put any kind of reasonable number" on how much his total defense could cost, said Kenneth Gross, a lawyer at a Washington law firm who specializes in political law and ethics. "But lawyers are not cheap."
Menendez allegedly accepted favors from a longtime friend and donor, Florida eye doctor Salomon Melgen, in exchange for the senator's political sway. According to Gross, Menendez can use a combination of funds—including money from personal, campaign, and PAC coffers—to provide for his legal defense.
Menendez's net worth, about $450,000 according to the latest available data, is paltry compared with his fellow members of Congress. He ranks 82nd in the millionaires club that is the U.S. Senate, where in 2013 the average senator was worth more than $10 million.
By 2014's end, Menendez's campaign committee had a little over $1.45 million cash on hand. And his New Millennium PAC, another potential source of funds, had about $140,000.
"He could settle it, it could be dropped, it could have to go to court," said Gross, of law firm Skadden, Arps, Slate, Meagher & Flom. "So it could be from thousands to millions, depending on whether we're talking about a full trial and appeals, or anything else."
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The case of former Sen. Ted Stevens of Alaska highlights just how high legal bills can climb. Stevens was charged in 2008 for concealing expensive gifts in financial disclosure statements. All in all, the legal fees associated with his trial totaled about $5 million.
The Stevens case, though, may have been an outlier: Gross said it was so expensive because Stevens went through a full trial and appeals process. "That was the full monty," he said.
As news reports continued to come out about Menendez's relationship with Melgen in 2014, his now-more-than-a-year-old trust fund took in more than 120 contributions, including money from Hispanic-market radio company Spanish Broadcasting Systems, which Menendez was scrutinized for trying to help in a 2003 merger. Last year, the trust took in $866,000 and spent $762,000, according to OpenSecrets.org, the website of the nonpartisan research group the Center for Responsive Politics.
Gross said senators don't typically have legal defense funds lying in wait for a potential legal misstep. Rather, funds are established if senators have a "reasonable anticipation" of needing them. For Menendez, that's years of ethical probes.