That's saying a lot, because the Nevada Democrat has had a reputation for being one of the dirtiest politicians in the sleaze- slinging business.
In an interview with the Huffington Post the other day, Reid charged that an unnamed investor at Bain Capital, the business investment company Mitt Romney founded, told him that Romney hadn't paid any federal taxes for at least a decade.
"He didn't pay taxes for 10 years," Reid stated flatly. "Now, do I know that's true? Well, I'm not certain," he said.
The incendiary charge, without an iota of proof to back it up, was bad enough, but he repeated it on the Senate floor where lawmakers can make all the false accusations they want and are Constitutionally protected from the libel laws.
Reid, apparently, believes he can make any claim he wants about Romney and get away with it. In this case, he was doing the dirty work in the midst of a very hard-fought campaign in which President Obama is in a dead heat with his well-funded Republican rival and could end up on the ash heap of failed, one term presidents.
Reid didn't just toss the charge out there and leave it at that.
No, he rubbed it in as if it were gospel truth. He had it on good authority, he said, though he isn't saying who that person is -- if in fact anyone really told him this.
"I mean, you do pretty well if you don't pay taxes for 10 years when you're making millions and millions of dollars," Reid said in the interview.
Later, he felt the need to elaborate further on what The Washington Post described as "Mr. Reid's unseemly drive-by" attack, saying that "a number of people tell me that."
This is the worst kind of smear politics possible, making unsubstantiated accusations against the political leader of the opposing party, charging that he was a tax dodger.
Reid has shamelessly produced no evidence to support his charges.
He knows the way the game is played. All you have to do is hurl an outrages accusation against Obama's opponent, knowing that there are people out there who will believe it.
"If the senator has any proof, he owes it to Mr. Romney, the presumptive Republican presidential nominee, to put it on the record, now," the Post said in a blistering editorial Wednesday.
"Otherwise, Mr. Reid ought to pause and reflect on the record of another senator who once claimed to have a list of Communists and spies at the State Department -- and could not substantiate it. Mr. Reid's smear tactics are not unlike those of Joseph McCarthy and deserve equal condemnation," the Post said.
Harry Reid's charges come on the heels of the Obama campaign's repeated attacks on Romney's decision not to release any further tax records beyond the 2010 and 2011 figures he has thus far made public.
Obama's attack squad suggests that Romney must be hiding something in his previous tax filings, even though he replied this week, "I have paid taxes every year, and a lot of taxes, so Harry is wrong."
Much if not most of the taxes Romney has paid since he left his former firm have been on his capital gains income from investments.
Those gains are taxed at a 15 percent rate, as provided for in the federal tax code, because the Congress in its infinite wisdom wants to encourage further investment in the U.S. economy.
That rate also helps ordinary older Americans who live off of their capital gains and dividends in their retirement years.
Romney knows that the only reason Obama and the Democrats want him to disclose all of his tax returns over the past 10 years is because they know it will show -- as his last two filings did -- that he paid the lower cap gains tax rate on most of his income.
And then of course they will use that information to play their political class warfare game which they're very good at, and thus hope to distract the voters from the issues that matter: four years of weak economic growth, 42 straight months of high unemployment, and an unbroken line of yearly, trillion dollar-plus budget deficits that have plunged our country into unprecedented debt.
Romney struck back on the Sean Hannity Show soon after Reid made his despicable charge. "Well, it's time for Harry Reid to put up or shut up. Harry's going to have to describe who it is he spoke with because that's totally and completely wrong," he said.
Was Reid doing the president's dirty work? That was the line of questioning Washington reporters fired off at White House press secretary Jay Carney this week.
Well, the president's spokesman chose his words very carefully, not wishing to criticize Obama's accomplice on Capitol Hill, but not wanting to suggest the White House was endorsing Reid's accusations, either.
With his back against the wall, Carney uncomfortably said Reid "certainly speaks for himself."
"I think the idea that people tell Harry Reid what to do is inconsistent with what everyone here understands...", he said, before being cut off by a reporter who asked why didn't the White House ask Reid to stop making charges he could not prove.
"This dispute is between the Romney campaign and Harry Reid...and Sen. Reid doesn't take direction, [he] speaks for himself," Carney replied.
But Romney's campaign surrogates rejected Carney's weaselly responses. "He [Reid] was encouraged to do stuff like this by [Obama campaign adviser David Axelrod], by the president and by the White House," former New Hampshire governor John Sununu told Fox News. "This is the way they operate. It is Chicago-style, gutter politics."
This is the kind of sordid, blood sport game Reid and the White House are playing -- the type of dirty politics that Obama railed against when he was running for president in 2008.
But Obama's spokesman can't even bring himself to say that the president categorically rejects the dirty attacks Reid is inserting into his campaign for a second term.
The underlying message now coming out of the White House seems to be that when you are in the fight for your political life, getting down and dirty is fair game.