HENRY C. JACKSON
WASHINGTON (AP) -- An ethical cloud is following Sen. Robert Menendez in Washington, even as he has leading roles in some of Congress' most important policy debates.
The New Jersey Democrat heads the Senate's Foreign Affairs Committee at a time when tensions with Syria, Iran and North Korea are rising. At home, the Cuban-American lawmaker is at the center of the immigration overhaul fight that's captivating Capitol Hill.
All the while, a Senate Ethics Committee investigation into Menendez's conduct persists, with many of the same questions about politics, money and influence that have dogged members of Congress through history: When does helping a supporter become a quid pro quo?
At issue is Menendez's relationship with Dr. Salomon Melgen, a Florida ophthalmologist under FBI investigation.
The two men have long and deep ties, and their relationship bears similarities to past congressional scandals, experts said.
Menendez has acknowledged several instances when actions he or his office has taken appear to have benefited Melgen. Menendez insists he's done nothing wrong.
"No one has bought me, No. 1. No one. Ever," Menendez has said. "In the 20 years I've been in Congress, never has it been suggested that that could even be possible. Never in 40 years of public life. So I'm not going to reach this moment in my life to make that a possibility."
It's a familiar Washington dance.
From the "Keating Five" scandal, one of the more celebrated congressional ethics cases, to more recent investigations, members of Congress have regularly run into trouble over the question of when helping a supporter crosses a line into impropriety.
"Most senators are doing this and you rarely get nailed for it," said Richard Painter, chief ethics lawyer under President George W. Bush and now a law professor at the University of Minnesota.
Menendez has run into trouble because "he didn't dot the i's and cross the t's. That allows (the Senate Ethics Committee) to open up a file and investigate."
Painter said that is similar to how past ethical scandals have unfolded.
During the Keating Five scandal, Sen. John McCain, R-Ariz., drew attention for flights he took on the plane of Charles Keating Jr., a top donor. Menendez's flights on Melgen's plane created a similar stir.
Ethical experts said Menendez's publicized actions are similar to those that have brought censure in the past.
"It's clear to me he crossed the line," said Melanie Sloan, a former federal prosecutor and the executive director of Citizens for Responsibility and Ethics in Washington, a watchdog group.
Sloan said Menendez's advocacy for Melgen on numerous fronts, particularly with federal regulators, is what makes his situation stand out as ethically questionable.
Lawmakers consistently find themselves on slippery terrain by helping donors, said Sheila Krumholz, executive director of the nonpartisan Center for Responsive Politics in Washington. She said that appeared to be the case with Menendez, too.
"We certainly have run across our fair share of scandals inspired by or really cemented by actions taken on behalf of donors," Krumholz said. "Often, too often, there's a nexus between top donors giving significant amounts of money and that money amounting to a significant return on investment."
She added, "Not a Congress goes by without there being some question of improper actions being taken."
Melgen is Menendez's top political donor. Last year, Melgen's practice gave $700,000 to Majority PAC, a super PAC set up to fund Democratic candidates for the Senate.
Aided by Melgen's donation, the super PAC became the largest outside political committee contributing to Menendez's re-election, spending more than $582,000 on the senator's behalf.
In January, Menendez reimbursed the doctor $58,000 for flights to the Dominican Republic aboard his private plane. Painter said Menendez's flights with Melgen were a red flag that elevated his case.
"It becomes a question of what other stuff is there," he said.
Menendez has acknowledged at least three areas where his official work appeared to serve the interests of Melgen, though he has steadfastly denied wrongdoing.
A staffer in Menendez's office sent emails to the Homeland Security Department in January questioning potential U.S. donations of cargo-screening equipment to the government of the Dominican Republic.
At the time, donated screening equipment could have jeopardized a lucrative port security contract for a company owned by Melgen. The government told Menendez's office that it had no plans to donate equipment. That came six months after Menendez himself raised concerns about the Dominican government's port security in a Senate hearing with senior officials from the State and Commerce departments.