In 2012, Republican presidential nominee Mitt Romney argued that Russia was “our number one geopolitical foe.” President Obama ridiculed his Cold War nostalgia. Romney was right -- as Russia’s subsequent aggression in Ukraine, Syria and elsewhere, and Vladimir Putin’s open hostility to the interests and values of the West, have made clear. The Cold War might not be back in full yet, but that’s not for want of trying on Putin’s part.

In 2016, the ignorant, unstable braggart the GOP nominated for president, Donald Trump, has views on Russia and its autocratic leader that make the Obama administration’s accommodation of Putin appear fiercely hawkish in comparison.

Trump has repeatedly expressed admiration for the Russian strongman, possibly finding in him a model of leadership that Trump, in his most fantastical delusions, might envision for his presidency -- one not constrained by international treaties, other branches of government, critics in the media, the Bill of Rights or the demands of a moral conscience.

He dismissed accusations that the former KGB operative is responsible for the murders of journalist critics. The latest victim, a Belorussian reporter critical of Russian aggression in Ukraine, was killed by a car bomb in Kiev last week. The U.S. “does plenty of killing also,” Trump argued, implying a moral equivalence between bombing terrorists and assassinating pesky reporters.

He brushed off Russia’s invasion of Crimea and its continuing aggression in eastern Ukraine as a European problem. He has signaled his desire to be a friend to Putin rather than an adversary, a friend who could appreciate Putin’s desire to reconstitute parts of the Soviet Union or claim a sphere of influence abroad that would compromise the sovereignty of a few NATO allies.

Trump, who has repeatedly called the treaty organization obsolete, recently voiced his reluctance to defend the Baltic republics should Putin invade them, as the U.S. is obliged to do under Article 5 of the NATO charter. That’s probably not an offer Trump, should he be elected, would have to make twice before Putin set about punishing Estonians for the effrontery of ridding themselves of Russian rule and resisting its continued meddling in their affairs.

In a press conference Wednesday, Trump said he was open to recognizing Russia’s annexation of Crimea, and lifting sanctions against Russia. He would acquiesce in the first invasion and expropriation of the territory of a sovereign European nation since World War II. For good measure, he threw in an invitation for Russia to keep hacking Hillary Clinton’s email server.

Trump campaign chairman, Paul Manafort, who’s had extensive business dealings with Putin’s crony oligarchs and was an influential adviser to former Ukrainian president and Putin toady Viktor Yanukovych, has laughed off speculation that there is anything nefarious or unusual about Trump’s views on Russia. A plank in the Republican platform supporting defensive assistance to the government of Ukraine was removed, reportedly at Manafort’s insistence.

For his part, Putin has made clear his reciprocal admiration for Trump. Various state-controlled Russian propaganda entities, including the English-language television network that broadcasts in the U.S. (Russia Today), regularly extol Trump’s virtues and criticize Hillary Clinton, whom Putin detests.

I’m sure Cold War Soviet leaders preferred some outcomes over others in U.S. presidential elections. But I’ve never seen it suggested that they openly advocated for a candidate or used Soviet intelligence networks to influence those outcomes.

That appears to have changed in 2016. Russia is probably responsible for hacking the DNC email server and providing to WikiLeaks the emails that caused a kerfuffle at the Democratic National Convention by revealing that the DNC leadership didn’t want Bernie Sanders to be their nominee.

It’s a risk bordering on the insanely reckless for Putin to intervene so directly in an American election. Trump probably won’t win, and I can’t think of anything more likely to encourage a harder line toward Putin’s adventurism by the next U.S. president than Putin’s meddling in our election. But evidence of Russian interference is getting hard to ignore. Putin has used Russian media to advance favored candidates and political movements in European countries. And he shares with Trump an insatiable hostility to those who won’t show him the deference he feels entitled to, a trait that can compromise his judgment, as it does Trump’s.

What’s in it for Trump? His views on most policy issues, foreign and domestic, are mostly memorable for the willful ignorance that informs them. They are often changeable. Why stick with the unorthodox position on Russia? As in everything involving Trump, there’s likely a profit motive involved. The Washington Post reported that Trump family members “have made numerous trips to Moscow in search of business opportunities, and they have relied on Russian investors to buy their properties around the world.”

Josh Marshall at TalkingPointsMemo, a partisan though usually careful news organization, observes that Trump’s debt load has increased dramatically and his past bankruptcies have made it virtually impossible to secure financing from U.S. banks. Trump has become “highly reliant on money from Russia, most of which has over the years become increasingly concentrated among oligarchs and sub-garchs close to Vladimir Putin.”

Could it be that a major party nominee for president is beholden to Russia’s leader and might compromise the security interests of the U.S. and our allies to maintain that relationship? We don’t know the answer. It’s scary enough that the scenario can’t be dismissed out of hand as a far-fetched Hollywood plot or a delusional rant from the fever swamps of American politics.

We can’t begin to answer the question until Trump releases his tax returns for the last several years. The media should make this the focus of every interview with Trump and senior Trump staff. The Republican Party chairman should urge him to release his returns. The Republican leadership in Congress should insist on it. Every American voter should demand it.

There are legitimate suspicions about whether Trump’s business relationships could compromise his loyalty to our country. Unless and until he puts them to rest, not by dismissing them but by disproving them, he should be considered unfit to hold the office of president.