In the short term, anyway, the tide of good news seems to have turned in favor of Robert Menendez.  

Officials in his old New Jersey congressional district named an elementary school for the Senate Foreign Relations chairman a few months ago. Then the Democrat celebrated his 60th birthday by announcing his engagement (in the Rotunda) to Alicia Mucci, a 45-year-old widowed constituent he’d met at a fundraiser.  

But the best publicity Menendez has enjoyed all year arrived Monday, when the Washington Post reported on evidence the Cuban government may have fabricated and planted the lurid story that has smudged the senator’s reputation since just before his 2012 re-election bid. Menendez crowed to CNN Tuesday that he “wouldn’t be surprised” if the regime in Havana had concocted the smear he had hired several underage Dominican prostitutes — because, he said, it “would do anything it can to stop me.”  

What all the righteous indignation and melodramatic skullduggery obscures, however, is that Menendez continues to face questions about behavior that’s far more legally and politically problematic than the already substantially discredited tales about his cavorting at sex parties in the Caribbean.  

For nearly two years, the Justice Department has been investigating whether Menendez illegally used his congressional office to benefit the business interests of his most generous donors, particularly Florida ophthalmologist Salomon Melgen. The Senate Ethics Committee appears to have put its similar inquiry on hold in deference to the Feds.  

If federal prosecutors end up alleging Menendez broke the law, that would be a much bigger deal for the already dismal ethical reputation of Congress — as well as for the Democratic Party and Latino community — than whether an antagonistic nation was able to make headway with an ambitious conspiracy to ruin an influential lawmaker. Menendez is not only chairman of a prestigious committee , but he’s a senior member of two other powerful panels. Next year, he’ll be the third-ranking Democrat on Banking and will advance to No. 6 in party seniority on Finance. So his becoming enmeshed in an ethical imbroglio could complicate a broad array of legislation.  

The senator is a formidable fundraiser for his party and one of the most articulate and outspoken voices at the Capitol for big-government liberalism. He also is a symbol for the nation’s fastest growing ethnic group and a crucial part of the Democratic base as the party’s only current Latino senator. (He was the first Hispanic from either party in congressional leadership, capping his seven-term House career with three years as chairman of the Democratic Caucus.)  

The federal investigation that threatens to unravel that path-breaking career is reportedly focused on at least two aspects of the relationship between Menendez and Melgen, who stands as the senator’s top donor of the past decade because of the sums he’s donated directly to the senator and to allied political action committees.  

There is evidence Menendez intervened with senior officials at the Department of Health and Human Services five years ago, after a Medicare audit found $8.9 million in questionable billings for eye treatments at Melgen’s clinics. (A database of all physician billings to Medicare, made public in April , showed Melgen was reimbursed $20.8 million for treating the elderly and disabled, the most of any other doctor in the country. His 894 patients underwent 94,000 procedures in 2012, according to the database.)  

There are also reports Menendez pressed State and Commerce officials to help a port security firm partly owned by Melgen when it was seeking to keep doing business in the Dominican Republic.  

The doctor also is a central player in the story alleging Menendez paid for prostitutes, because the pair were said to have flown on the physician’s jet during the congressional spring recess that year for trysts with teenagers at a plush resort. Taking travel gifts is rarely allowed under Hill ethics rules. Since the story was first published in the Daily Caller in November 2012, Menendez says he or his campaign have reimbursed Melgen $70,000 for a handful of flights dating to 2010.  

Having corrected those “oversights,” as he’s termed them, Menendez says there is nothing improper about his time in the Dominican Republic.  

And on Tuesday he and his lawyer asked President Barack Obama’s administration to pursue all evidence that Cuban intelligence agents cooked up the libidinous tale and invented a tipster named “Pete Williams” to peddle the story to several American and Latin American media outlets. The Post reported that last year the CIA relayed credible evidence of such a plot to the FBI’s counterintelligence division.  

In Menendez’s view, the motive for such an outside-the-box effort is obvious: The senator, the son of Cuban immigrants, is probably the most passionate opponent in Congress for thawing relations with Cuba, so it would behoove the Castro regime to tarnish him so completely that he could never wield the gavel of committee that drives congressional foreign policy.  

If that was the idea, the Cubans showed remarkable foresight. “Pete Williams” first surfaced six months before the 2012 elections, when it was far from clear there would be an Obama second term — let alone that John Kerry would then be asked to leave the Senate for the State Department, the move that landed Menendez the Foreign Relations gavel.  

But the theory of Cuba as culprit has been circulating among the senator’s allies since the moment Menendez took over. “He’s been so steadfast against the Castro government. He’s been a critic all his political life,” Rep. Albio Sires, who succeeded Menendez in the House, told the Newark Star-Ledger in February 2013. “I would not be surprised if they are behind some of this stuff, some of these allegations.”