The language was jarring: The New York Times reported that the FBI had started an investigation into whether the sitting president of the United States was "working on behalf of Russia against American interests." This was followed by stories in other outlets suggesting President Trump's behavior toward Moscow may have been nefarious.

When greeted with a headline like "FBI Opened Inquiry Into Whether Trump Was Secretly Working on Behalf of Russia," a reader might expect to find shocking new information. Instead, the rationale for the FBI probe appeared to be all the standard reasons for Trump-Russia concern that have been out there for years: the firing of FBI Director James Comey, campaign trail comments about Russia and Hillary Clinton's emails, changes to the Republican platform. All of these are significant matters of interest. But in discussing Trump-Russia, it is important that we distinguish between the potentially criminal or suspicious, and the legitimate, if debatable, policy disagreements.

Any collusion with Russian electoral interference, hacking Democratic emails, former Trump campaign chairman Paul Manafort's financial affairs — those things are potentially criminal. And the possible lifting of sanctions on enterprises associated with Russian oligarch Oleg Deripaska is certainly suspicious. Other things, like pulling troops out of Syria, rethinking an alliance, or attempting diplomacy with Putin may be right or wrong. But they are not positions that ought to be criminal acts.

What would really have increased the public's understanding of the Trump-Russia affair is not just learning that an investigation exists and why, but understanding what details said investigation actually uncovered. In the absence of such revelations, some details did stand out: Alongside the questions of whether Comey's termination was related to the still-ongoing Russia investigation and as such might have entailed obstruction of justice, we learned that "investigators had watched with alarm as the Republican Party softened its convention platform on the Ukraine crisis in a way that seemed to benefit Russia." They also did not like the way candidate Trump talked about Russian President Vladimir Putin.

Whether the U.S. should intervene in a standoff between Ukraine and a nuclear-armed Russia is a perfectly acceptable thing for a major American political party to debate. And as for changes to the Republican platform, the language adopted at the convention that nominated Trump was hardly pro-Putin. It in fact faulted former President Barack Obama for presiding over a "resurgent Russia occupying parts of Ukraine and threatening neighbors from the Baltics to Caucasus," trying to "curry favor with Russia," and allowing "Russia to build up its nuclear arsenal while reducing ours."

"We support maintaining and, if warranted, increasing sanctions, together with our allies, against Russia unless and until Ukraine's sovereignty and territorial integrity are fully restored," the Trump GOP platform stated. "We also support providing appropriate assistance to the armed forces of Ukraine and greater coordination with NATO defense planning." The platform further pledged to "meet the return of Russian belligerence with the same resolve that led to the collapse of the Soviet Union."

All that was missing was an amendment that promised Ukraine "lethal defensive weapons." The delegate who proposed that language later told the Washington Examiner's Byron York, "The platform ended up tougher than it started, compared from the beginning to the end."

Then came reports Trump discussed leaving NATO "amid new concerns over Russia." Leading Democrats had already said Trump's proposed withdrawal from Syria, supported by many lawmakers and even some presidential candidates in their own party, was a "great big Christmas gift" to Russia and Iran. But the NATO alliance was made to fight a Cold War America won nearly 30 years ago. It has long outlived its Warsaw Pact counterpart. Rethinking this treaty may be unsavory for Democrats, but it is not a crime.

There is no need to make crimes out of Trump's deviations from the foreign policy status quo. The allegations against Trump and his associates are serious enough. And the Constitution does not give the FBI the sole authority to determine what policies advance American interests.

Progressive writer Glenn Greenwald notes that the FBI was once similarly suspicious of former Vice President Henry Wallace, surveilling a duly elected constitutional office-holder over his reluctance to take a more confrontational stand toward the Soviet Union. As it happens, there was attempted communist subversion in the United States and I think many of Wallace's foreign policy views were wrong. But the historical record has also shown J. Edgar Hoover's FBI's propensity to overreact in these cases, to the detriment of civil liberties.

We can confront Putin's illiberalism and interference without recreating that climate of McCarthyite excess in our own time. There should be a bright line between policy differences, and the kind of actual crimes Special Counsel Robert Mueller was appointed to investigate.