When an American president speaks with President Vladimir Putin of Russia on major international issues of disagreement, it should be a forthright discussion. Or some variation on that theme of diplomatic disagreement.

The White House should not reference, as it did on Friday, a "very positive" call. After all, the White House says the two leaders discussed North Korea, Ukraine, Venezuela, nuclear arms control, and the Mueller report. And Putin's interests are very much in conflict with our own on each of those issues.

On North Korea, Putin is undercutting Trump's effort to persuade Kim Jong Un to abandon his nuclear and long-range ballistic missile programs. Putin sees North Korea as an opportunity to destabilize U.S. security, and Russia's pathway towards a South Korean port network. The Russian leader has little concern over Kim's retention of nuclear weapons. Indeed, as those weapons threaten America, Putin's government finds it funny.

On Ukraine, Putin wants to sever Crimea and two other southeastern provinces from the Ukrainian government. Pursuing that objective, Putin mixes a combination of irregular warfare, temporary cease fires (as in Syria), and intelligence action to control the highways between Mariupol, Donetsk, and Luhansk. Trump has actively countered these efforts, but it is impossible that Putin had anything good to say about the issue on Friday, because Putin is not quitting in Ukraine.

On Venezuela, Putin has taken advantage of Trump's hesitation to consolidate Nicolás Maduro's illegitimate regime. This has damaged U.S. foreign policy credibility in Latin America.

On nuclear weapons, Putin is developing next-generation weapons that boost Russia's first strike capability. While Putin might be inclined to reduce his nuclear warhead stockpile, his recent destruction of the INF treaty and his forward deployment of nuclear strike forces indicate his desire to degrade U.S. security. Trump should thus have had only one message for Putin on Friday: if you keep boosting your nuclear strike efforts, America will keep ensuring we can defeat you in a nuclear war.

On the Mueller report, White House press secretary Sarah Sanders noted that Trump and Putin welcomed the end of that investigation. That's understandable from Trump's point of view. Still, the U.S. president should not be having a pleasant conversation with Putin over this issue. The Russian leader is directly responsible for targeting the 2016 elections and the 2018 elections. Either in favor of, or against Trump, Putin will conduct that same aggression in 2020 unless deterred.

This is not to say that Trump and Putin shouldn't speak or even be civil. But no American president should regard a phone call with Putin as "very positive" when it goes over issues where there is an irreconcilable difference in views. To do so is to delude oneself that Putin has an interest in shared compromise. On the matters of consequence, he does not. Putin is a KGB officer who never truly left the KGB. He lives to weaken America.