Michael Flynn’s resignation — under fire — as national security adviser has the larger question of Donald Trump’s relationship with Russia back in the news. It’s a story that centers on three big, but fundamentally unproven, allegations: that Trump is on the take from Russia, that he is somehow exposed to Russian blackmail material, that his campaign actively collaborated with the Russian government during the 2016 campaign, or some combination of the above.

The evidence for those explosive charges is thin.

What we have instead are a lot of small, unanswered questions. Questions about Flynn’s behavior and the circumstances of his firing. Questions about the behavior of former Trump campaign manager Paul Manafort and the circumstances of his firing. Questions about enigmatic remarks made by longtime Trump associate and veteran political operative Roger Stone. Questions about an obscure American businessman named Carter Page who maybe — or maybe not — worked for some time with the Trump campaign.

But there are also longstanding questions about the opaque financing of the Trump Organization, and about why its founder and owner has been so reluctant to engage in normal levels of financial disclosure. And most of all, there are questions about Trump’s highly unorthodox attitudes toward Russia, its government, and its leader, Vladimir Putin.

Here, in convenient list form, are the 30 small questions and three big ones about Donald Trump and Russia.

Five questions about Michael Flynn

Michael Flynn was a well-regarded, if somewhat unorthodox, Army officer who was promoted to head the Defense Intelligence Agency. There, he clashed with colleagues over disparate visions for the structure of the overall intelligence community and with the Obama White House over Iran policy. He was fired and sent to the fringes of the policy community, from whence he returned with out-of-the-mainstream opinions on Islam and Russia policy, a close association with the Russian television network RT, and an affiliation with Donald Trump’s presidential campaign.

A top aide to the president, he was recently fired as part of the fallout of a telephone call with Russia’s ambassador to the United States, Sergey Kislyak, during which they discussed the Obama administration’s imposition of sanctions to punish Russia for interfering in the American election. Trump says Flynn was fired due to a loss of trust between the two men, but that Flynn’s underlying conduct in making the call was fine. But:

What exactly did Flynn say or do that caused the president to lose trust in him?

Why did Flynn tell the public (and Mike Pence and even the FBI) that he didn’t discuss sanctions with Kislyak when he did discuss them?

Who, if anyone, authorized or directed Flynn to call Kislyak and discuss sanctions with him?

Kislyak and discuss sanctions with him? What, if anything, did Flynn promise Kislyak in exchange for Russia forgoing retaliation to sanctions?

Why did White House officials continue to say that Flynn hadn’t discussed sanctions with Kislyak for days after the White House counsel was told that he had?

Three questions about Carter Page

Carter Page was an American businessman of no particular renown who worked in the Moscow office of Merrill Lynch before striking out on his own with a consulting company. Nobody in Washington — and few people in Moscow — seems to have heard of him when Trump started naming him as a member of his then-threadbare national security team. The résumé boost seems to have been a boon to Page’s stature in Russia, where he portrayed himself as a big shot in ways that ended up being a liability to Trump.

His association with the Trump team ended rapidly, and Trump has ever since been at pains to minimize the degree of contact he ever had with Page.

Five questions about Roger Stone

Roger Stone is a veteran Republican Party political operative dating back to the Nixon administration, when he was a leading perpetrator of “dirty tricks” politics. By the 21st century, he was a marginal figure in national GOP politics but continued to be a player in New York via his connections to former New York state Senate Republican leader Joseph Bruno (who was later convicted on multiple corruption charges that were eventually overturned). He’s also a longtime friend of Trump’s, and a bridge between pre-campaign Trumpworld and the world of politics.

His exact role in the evolving Trump campaign is unclear, but he has at various times appeared to be strikingly in the know about the goings-on of WikiLeaks, and anonymously sourced news articles have suggested his ties to Russian government figures are the subject of ongoing investigation.

Five questions about Paul Manafort

Paul Manafort, like Stone, is an old-line Republican Party operative who’d somewhat fallen out of the national party mainstream. But while Stone became a colorful domestic figure, Manafort sought his fortunes abroad — offering consulting and lobbying services to an array of unsavory foreign governments, and eventually finding work for Ukrainian politician Viktor Yanukovych and his Party of Regions, Moscow’s main vehicle for influence in Ukraine during the 21st-century tug of war for dominance over that country.

Seven questions about the Trump Organization

Donald Trump’s financial disclosure forms reveal essentially nothing about his underlying finances, because all they show is that he is the full or partial owner of a sprawling array of limited liability companies that together comprise the Trump Organization. These are privately held “pass-through” entities, whose profits and losses show up on the individual income taxes of their owners — Trump and his partners.

Because Trump has not disclosed his tax returns, this means we have no real idea how his businesses operate or where they get their money. Trump loudly proclaims he has no deals in Russia, but the physical location of deals is not the issue. And Trump has not amassed the kind of sterling record of honesty that should make anyone inclined to simply take his word for it.

Five questions about Trump’s policy toward Russia

Before Trump arrived on the scene, the overwhelming consensus in Republican Party politics was that the Obama administration had been too soft on Russia. Republicans believed the New START Treaty made too many concessions to Moscow, that Obama had not intervened forcefully enough against Russia’s allies in the Syrian government, that he had not done enough to back the Ukrainian government, and that he had committed insufficient military resources to the defense of Central Europe.

Trump reversed all that. And while seeming very flexible on most policy matters, he has remained quite rigid in his insistence on replacing the GOP’s old “more hawkish on Russia than Obama” stance with a new “more friendly to Russia than Obama” stance.

The three big questions about Trump and Russia

A lot of these details are essentially trivia, but they add up to a few big, explosive questions about why the president of the United States keeps needing to distance himself from his own associates, won’t reveal what’s going on with his money, and insists on advancing an unusual foreign policy doctrine.

Did the Trump campaign, directly or indirectly, actively collaborate with the Russian government over the course of the 2016 campaign?

Is the Trump Organization benefiting from ongoing or recent financial flows from the Russian government or people close to it?

Does the Russian government have dirt on Trump, relating to past shady financing or to some of the more salacious blackmail material alleged in the infamous “Steele dossier,” that’s influencing American policy?

The small questions ensure the big questions won’t end

“Where there’s smoke, there’s fire” is a good dictum for forestry management but doesn’t really apply to politics.

Politicians try to avoid embarrassment, and a simple desire to own up to something embarrassing — rather than anything illegal or genuinely nefarious — often lies behind mysterious behavior. It’s entirely possible that Page ended up on the roster of Trump advisers simply because a disorganized campaign was taken in by a grifter. Trump’s refusal to engage in standard financial disclosure certainly seems to be about covering up something, but that something could have nothing to do with Russia.

The shifting and inconsistent stories about the Flynn timeline could be nothing more than a disorganized and distrustful White House staff bungling something and then compounding the bungling by not wanting to admit they were bungling.

Trump’s boast about meeting with oligarchs could just be a habitually dishonest person lying for no particular reason.

But especially in light of Trump’s unorthodox policy views on Russia, the sheer quantity of outstanding questions and loose threads is remarkable.

That’s doubly so because the Trump team has repeatedly tried to have it both ways on a number of these fronts — with Stone, Manafort, Page, and Flynn all distanced from Trump once their Russia connections came to light, even as Trump denies there was any underlying wrongdoing and appears not to have fully severed ties.

Trump has repeatedly, and increasingly angrily, suggested that the answer to the three big questions is uniformly no. But his inability to provide satisfactory answers to the myriad other questions means it’s hard to take him at his word.

Watch: How Putin won Republicans’ approval