The Washington Post's Carol Leonnig and Tom Hamburger explain the Trump Organization's efforts to build a Trump Tower in Moscow. (Jenny Starrs,Meg Kelly/The Washington Post)

Evidence that then-presidential candidate Donald Trump was pursuing a lucrative business deal with Russia and that his personal attorney, Michael Cohen, emailed Russian President Vladimir Putin’s personal spokesman to intervene raises the stakes in Robert S. Mueller III’s investigation substantially. The Post reports:

Cohen’s email to [Dmitry] Peskov provides an example of a Trump business official directly seeking Kremlin assistance in advancing Trump’s business interests. … Cohen said he discussed the deal three times with Trump and that Trump signed a letter of intent with the company on Oct. 28, 2015. He said the Trump company began to solicit designs from architects and discuss financing.

Ethics expert Norman Eisen warns: “Now we have a second group of emails from those in Trump’s orbit suggesting high-level outreach to Russia in and around the election season. Like the now-famous email exchange with Don Jr. about Russia’s ‘support for Mr. Trump,’ these new documents promising that ‘Putin’s team’ will ‘buy in’ on Trump raise the question of what the president knew of all this and when he knew it.” He tells me, “The emails add important additional evidence to the special counsel’s investigation, both as to possible collusion and as to obstruction of justice, inasmuch as they deepen the suspicion of a possible malign Trump motive for attempting to block the Russia investigation.”

Now, Cohen insists to The Post that the Trump Tower Moscow proposal was “not related in any way to Mr. Trump’s presidential campaign.” But of course, we don’t know that and neither does he. Mueller, however, will be looking for evidence, as Eisen puts it, “that Trump or his agents actually agreed to better treatment for Putin and Russia in exchange for a present or future Trump Tower Moscow.” That would, he says, “go beyond collusion to outright corruption.” But even without a smoking gun showing a quid pro quo, the extent to which Trump was compromised — and may remain so — should concern Congress and the voters.

Was Trump trying to keep on Putin’s good side to advance his deal? Did he think Putin was someone the United States could do business with because he was seeking to do business with Russians? Trump’s effort to conceal his finances and mislead the public about business dealings, with a foe of the United States no less, may have affected his rhetoric and decisions in ways we have yet to discover.

As we learn more about Trump’s Russian dealings, his actions in trying to shut down the investigation become more understandable. “These new emails make the obstruction charge more substantial, because it gives heavier context to the cover-up,” says Fordham law professor Jed Shugerman. “There was fire under all that smoke. The firing of Comey was already impeachable as obstruction, but it’s politically more powerful in connecting the cover-up to real corruption.”

The extent of Trump’s political and legal jeopardy slowly comes into focus with new, daily discoveries. Clint Watts, a former FBI special agent (who has testified on Russian meddling) and now a fellow with the Foreign Policy Research Institute, tells me, “Trump’s claims to have nothing to do with Russia are clearly false with revelations Cohen emailed the Kremlin directly to gain support for a Trump Tower Moscow. Trump’s laudatory comments of Putin came at times when Trump’s companies also sought Kremlin-assisted business help.” He continues, “Some will interpret Felix Sater’s comments as over-the-top salesmanship leading to no direct connections with the Kremlin. But why would Sater believe he would get ‘Putin on this program’ and that the Kremlin could get Trump elected?” Unless Sater chooses to take the Fifth Amendment, we won’t have to guess; Mueller’s team will no doubt question him and include the findings in his final report.

Some in Congress are disturbed that Trump himself has not been forthcoming or, indeed, has been misleading about his Russia dealings. Rep. Elijah E. Cummings (Md.), ranking Democrat on the House Oversight and Government Reform Committee, tells me, “If this new report is true, why wasn’t this disclosed sooner? Why, like so many times before, are the American people forced to find out new details about the President’s relationship with Russians from strong investigative reporting instead of from the President himself?”

All of this comes in the context of Trump’s eagerness during the campaign for Russia to hack and release Hillary Clinton’s emails. “[The Cohen] emails came at a time when Russia’s hacking teams breached the DNC and numerous other American targets and Russian media began promoting Trump even though he seemed nothing more than a reality TV star looking for attention,” Watts observes. “For those that continue to deny Russian meddling, I can’t imagine what additional evidence they would need to know that Russia sought to elect Trump, and Team Trump wasn’t averse to it, and maybe even hopeful for it.”

The interaction of Trump’s personal finances with foreign powers should also remind Congress and voters that Trump continues to receive money through his businesses from foreign governments, be they be in the form of bookings at his hotel or benefits derived from expedited trademarks. This is the essence of financial corruption — when someone benefits financially because of his official position. The extent to which it affects judgments on policy issues invariably remains murky. And in the case of Trump — who assumes anyone who likes him and treats him well is a “good guy” — the combination of personal finances and presidential powers is unconscionable.

Republicans have refused to address this issue in any serious way, allowing the conflicts to fester and Trump’s finances to remain opaque. Congress has the power to legislate — to disallow emoluments, require divestiture of businesses, bar relatives (with their own holdings) from serving in government and mandate disclosure of tax returns. In failing to take any action, Republicans are complicit in Trump’s debasement of the presidency and of our democracy.

So long as Republicans retain the majority in both houses, the problem will deepen. Either their indulgence of Trump or their majorities must go if we are to reestablish normal government and reject foreign corruption of our political system.