The cloud that President Donald Trump has complained hovers over him not only remains after Thursday's sworn testimony of former FBI Director James Comey, it has grown darker.

Comey's detailed answers leave little doubt that Trump attempted to pressure him into dropping the investigation of former National Security Adviser Michael Flynn. While Comey declined to draw any conclusions about whether Trump had acted to obstruct justice, the facts he laid out could constitute credible elements for such a case.

That Trump was not personally being investigated is a red herring. His campaign and his White House were. Another distraction is the focus by some on Trump expressing his "hope" — rather than a direct order — that Comey would let go of Flynn. Trump cleared the Oval Office to make his request, including dismissing Comey's direct superior, Attorney General Jeff Sessions. Sessions' role also bears further scrutiny. He had not yet recused himself from the investigation into Russian election meddling at that point and was honor-bound not to leave his subordinate to face the pressures of the president alone. Little wonder that Comey did not immediately apprise Sessions of the conversation.

The sheer number of interactions between the new president and Comey is staggering — nine over several months, including phone calls, meetings and a private dinner. Compare that with the two meetings Comey had with President Barack Obama over three years. Trump pressed Comey for his loyalty in a way that was thoroughly inappropriate for a law enforcement official who must remain neutral. House Speaker Paul Ryan's defense of Trump's innocence by pleading his ignorance is embarrassing, and dishonors him and Trump alike.

Comey's testimony shows a president clumsily attempting to intimidate a top law enforcement official and, when that fails, firing him on a thin pretext in the most publicly humiliating way possible. In his testimony, Comey said the White House told "lies, plain and simple," about why he was fired. He explained his meticulous note-taking of every interaction with Trump by saying he feared the president might lie about what transpired.

Trump, through his personal lawyer, wasted no time in declaring Comey to have lied about the demand for loyalty and the request to drop the Flynn investigation. Trump's lawyer then declared his client had been "completely vindicated" because Comey had said under oath that Trump was not personally under investigation. Apparently, that part of Comey's testimony was believable.

Comey acknowledged leaking a memo detailing his interactions in an effort to speed the appointment of a special counsel, and thank goodness he did. The work of Special Counsel Robert Mueller, who is pressing ahead with a wide-reaching investigation, is vital. So too are the efforts of the Senate Intelligence Committee, which has succeeded in bringing some facts to the public. Much more is needed. The extent of Russian involvement and any connections to the Trump campaign and White House must be known.

As part of its probe, Congress should, at long last, exercise its authority to obtain Trump's tax returns and examine any financial ties to Russia. The earlier refusals by National Intelligence Director Dan Coats and Mike Rogers, director of the National Security Agency, to answer senators' questions about whether Trump tried to sway investigative efforts should not be tolerated. Short of revealing classified information, they should cooperate fully with Congress.

The matter that confronts Americans is extraordinarily serious. The president has an unhealthy admiration for and an untoward number of contacts with a longtime nemesis of this nation. That same nation has interfered in a U.S. election. Americans must know the extent of that interference and whether their president — or those close to him — aided or attempted to cover up those efforts.

In Comey's own words, this is a big deal, and it's not about Republicans or Democrats. Russians are coming after America, he said. "They want to undermine our credibility in the face of the world. They think this great experiment of ours is a threat to them, and so they're going to try to run it down and dirty it up as much as possible."

Americans must make it their business to stop them.