Before Donald Trump and his language manipulators can really plan to “drain the swamp,” as they like to say, he and his cohorts need to stop fouling the air. The “swamp,” as we well know, is Washington and its stagnant slime of corruption, combined with an atmosphere of deception. The stench of D.C. air is particularly bad these days, worsened by the constant smoke screens deployed to manipulate reaction to the outrages that permeate the infant — make that infantile — Trump presidency.

Blatant lies pile upon blatant lies, followed by buffoonish rationalizations designed to obfuscate — smoke screens, in other words. None of them was more obvious than the attempt by House Intelligence Committee Chairman Devin Nunes to confuse the folks about the overwhelming evidence that Trump’s Twitter tantrum was utterly false when he banged out on March 4: “Terrible! Just found out that Obama had my ‘wires tapped’ in Trump Tower just before the victory.”

Since then, Trump and his accomplices have tried to wriggle out of that one, but each attempt has been met with increasingly authoritative rejection of the entire claim. None was more devastating to Trump than the testimony of FBI Director James Comey and National Security Agency Director Mike Rogers, who is in charge of the government’s electronic surveillance, that nothing of the sort happened. They were appearing at a rare public hearing of House Intelligence to discuss the allegations that Donald Trump and/or his people colluded with Vladimir Putin and the Russian government to throw the election Trump’s way. We learned that the FBI is taking that charge seriously enough to be engaged in a full-scale investigation. We also learned from the ones who would know that the surveillance accusation against President Barack Obama was total bunk.

Nunes holds a uniquely powerful position in Congress: He is chairman of the oversight committee that oversees (hence the name) the ultrasecret intelligence activities of the United States government.

Due to their sensitive assignment, the committees (the Senate has one, too) are supposed to be unusually bipartisan, majority and minority members dealing with the nation’s most classified information without the taint of politics.

Nunes insists that his committee is the proper place to investigate the explosive Russian charges, not a special body, called a “select committee” in congressional parlance or an independent commission. His ranking member (Washington-speak for the leading minority member) is California Democrat Adam Schiff. Usually, where you see one publicly, you see both. But not last Wednesday.

That day, Nunes, who has struggled to maintain an image of being impartial despite the fact that he served on Trump’s transition team, obliterated any chance of his credibility being taken seriously when he struck out on his own. Regarding the discredited tweet storm about Obama, which is really a sideshow for his committee, Nunes suddenly, without consulting Schiff, appeared not once but twice before reporters, announcing he had viewed, but didn’t possess, intelligence that “seems to me to be some level of surveillance activity — perhaps legal, but I don’t know that it’s right.”

He outlined a vague, and contradictory, description of “incidental” scooping up and identifying Americans while spying on foreign citizens, the only ones whom U.S. agencies can legally target. He shared what he claimed to have seen with President Trump, which also was bizarre since it’s the president and his people who are under investigation. What we had then was a classic smoke screen, which allowed Trump to claim he was “somewhat” vindicated.

Predictably, Schiff was furious, or in more Washington-speak, he had “grave concerns”: “The chairman will either need to decide if he’s leading an investigation into conduct which includes allegations of potential coordination between the Trump campaign and the Russians, or he is going to act as a surrogate of the White House. Because he cannot do both.”

Nunes subsequently apologized to the members of his committee for the way he blew smoke without telling them he would.

The Democrats made it clear that they believe his credibility is shot. The swamp’s ooze grows even thicker.