Just when you thought Washington couldn’t get worse, we’re swamped by sensational headlines and breathless reports about Russia, wiretaps and criminal leaks of classified material.

Throw in a leading congressman’s late-night meeting at the White House, and it all has the feel of a second-rate movie plot. But don’t you dare tune out, because we are witnessing an unprecedented event: two potential Watergate-sized scandals involving two presidents are emerging simultaneously.

Did Donald Trump collude with Russia to defeat Hillary Clinton? Did Barack Obama politicize law enforcement and intelligence-gathering to spy on Trump and destroy his presidency?

Those are extraordinary questions, all the more so because the race to answer them is happening on parallel tracks. The usual partisanship has become a winner-take-all war to paint the other side’s president as guilty of un-American conduct.

Scandal No. 1 started with reports that Russian hackers tried to tip the presidential election to Trump. Soon came the added charge that Trump’s team was working with Vladimir Putin, as described in the discredited dossier about Russian hookers.

Clinton insisted often that Trump was guilty of something, and her media handmaidens still fan the smoke in a desperate search for flames. Though there is zero evidence so far, the continuing FBI investigation gives Democrats an opening to make up their own facts, as House Minority Leader Nancy Pelosi did Friday by suggesting that Russia is blackmailing Trump.

The next piece of collusion evidence will be the first, but that hasn’t stopped the left’s fantasies about impeaching Trump. Some are breaking the law to build their case.

That brings us to Scandal No. 2, which got a late start, but it’s moving fast and is closer to pay dirt. As far fetched as it might have seemed when Trump first charged that Obama “wire-tapped” him, there is compelling evidence that Trump was onto something very big.

Numerous media reports continue to reveal that federal agents gathered secret information about Trump’s team and used it to sabotage him. If it can be proven that a sitting president used government authorities to spy on a candidate who then became president and orchestrated leaks of classified material, Watergate, by comparison, really would be a second-rate burglary.

The odds favor the possibility that Obama was the king of dirty tricks. Consider that Evelyn Farkas, a former Obama defense official whose portfolio included Russia, said in a March 2 interview that was little noticed until last week that she had urged the Obama White House and congressional Dems to gather information about Trump and protect it from the new administration.

“If they found out how we knew what we knew about their, the staff, the Trump staff’s dealing with Russians, that they would try to compromise those sources and methods, meaning we would no longer have access to that intelligence,” Farkas told MSNBC. “So I became very worried, because not enough was coming out into the open, and I knew that there was more.”

She added: “We have good intelligence on Russia . . . That’s why you have the leaking. People are worried.”

Farkas later tried to walk back her claims, but too late. Her next speech should be to a federal grand jury.

Her apparent admission that national security leaks came from Obama officials working to undermine Trump is a major development, and The New York Times added an important wrinkle Friday. Perhaps inadvertently, a Page One story dropped the usual reference to surveillance on “Trump associates” and cited “intelligence reports that showed that President Trump and his associates were incidentally swept up in foreign surveillance by American spy agencies.”

To my knowledge, that is the first report anywhere to say that Trump himself was picked up on surveillance. If true, it’s a bombshell that changes everything.

When was Trump overheard? Who was he talking to? How does the Times know it was “incidental” instead of intentional, except that a leaker said so?

The story doesn’t answer those questions, yet says Trump’s claim of being wiretapped was “debunked.”

Wrong. It’s been denied, but hardly debunked.

Furthermore, it’s a crime for anyone to leak Trump’s name to the Times and to “unmask” any American citizen who was not the target of surveillance. Yet Trump is at least the sixth person from his circle to be publicly identified as being picked up by Obama-era surveillance.

The accumulating evidence that Trump and his team were targeted by American agents is now properly part of congressional investigations, but the pattern also deserves a criminal probe.

Watergate references can be trite, but the end of Richard Nixon offers lessons about where we go from here. For one thing, finding and squeezing a knowledgeable insider is crucial, and Farkas is a good starting point for the Justice Department.

Because she later served as an adviser to Clinton’s campaign, it’s also worth exploring whether she was a conduit with the Obama White House, and whether she leaked secret data to the media.

A second Watergate lesson is that the war isn’t over until the home team waves the white flag. Recall that it was Republicans who convinced Nixon it was time to go.

So the GOP is key to the outcome of the Trump-Russia probe, and Dems will have a say about whether the leak investigation implicates Obama.

Here’s the really frightening possibility: What if both presidents turn out to be guilty? What the hell do we do then?

Gov, Blas are lefty cellmates

Gov. Cuomo and Mayor de Blasio are personal enemies but, politically, more like twins. Their desire to close Rikers Island is the latest example of their shared radicalism.

The leftward march is no coincidence. Both have their eye on a national Democratic audience even as they run for re-election: de Blasio this year, Cuomo next. Both also hope to get ahead by running against the policies of President Trump.

It’s hard to believe there’s room for another New Yorker on the national stage, with Trump in the White House and Sen. Chuck Schumer the big Dem dog in the Senate. Then again, Trump’s victory is convincing lots of long shots that lightning can strike them, too.

DeB’s tab? Put it on the house

Now that the city’s Conflict of Interest Board has slapped a $50 limit on “gifts” to Mayor de Blasio’s legal-defense fund, speculation grows that he’ll stick taxpayers with the bill.

Here’s a better idea: As I’ve noted, de Blasio owns two private homes in pricey Brooklyn, and a reader estimates their combined market value could be $5 million.

The mayor is rich, and can pay his own legal bills. He should sell the houses instead of sticking taxpayers with another corruption tax.

Haha, Bharara!

Preet Bharara hasn’t lost his sense of humor. The former federal prosecutor tweeted about Albany:

“#BREAKING: Bold, sweeping, principled ethics reforms finally enacted in New York State! The swamp, drained. #AprilFools.”