(Jacquelyn Martin/AP)

Sen. Robert Menendez is finally paying up on a promised IOU, but he’s just a little more than a day late and a dollar short.

The New Jersey Democrat’s most recent campaign filings show that he donated the tidy sum of $8,800 apiece to the Alzheimer’s Association of Greater New Jersey and Autism Speaks.

What a guy, right?

But he wasn’t motivated entirely by altruism — and the amount was just a hair under what he’d promised the nonprofits.

The donations were a way to get rid of tainted political donations from a shady donor (candidates may return illegal donations either by giving them to the U.S. Treasury or to a charity). The Record of Bergen County, N.J., noted in early May that Menendez had promised that the charitable donations were coming more than a year earlier. In the May story, he blamed a campaign attorney for the delay in writing the checks.

“I ordered it to be done,” Menendez told the paper at the time. “We checked our records and the law firm we hired to cut all of our checks and do all of our vetting failed to do so. So I told them they had to get it done today.”

Seems that this time, the lawyers got cracking. The money was handed over May 6.

Still, it wasn’t quite the full amount Menendez had originally offered. According to the Record, he had pledged to donate $18,800 of the money he received from insurance broker Joseph Bigica, who pleaded guilty to using straw donors to fill the senators’ campaign coffers.

But the two donations together only totalled $17,600. That’s $1,200 short of what he said was coming.

A Menendez spokeswoman tells the Loop that the campaign legal team reviewed the donations in question and determined that $17,600 represented the full amount of the illegal funds that need to be ditched.

Better late (and less) than never.