Michael Bociurkiw is a global affairs analyst and a former spokesman for the Organization for Security and Cooperation in Europe. Follow him on Twitter @WorldAffairsPro. The opinions expressed in this commentary are his; view more opinions on CNN.

(CNN) When Russia forcibly annexed Crimea in the spring of 2014, sending heavily armed masked men onto the peninsula that indisputably belonged to Ukraine, it triggered a collective gasp of disbelief across Europe. After all, it was the first time since the break-up of the Soviet Union that Russian troops occupied the sovereign territory of one of its former states.

Ukraine's pro-Moscow President had just been ousted during the Maidan Revolution, and the annexation of Crimea caught the transitional Ukrainian government by surprise. It also sent a chill down the spines of neighboring countries and triggered alarm bells at the United Nations.

At the time, the late Sen. John McCain, R-Arizona said : "Every moment that the United States and our allies fail to respond [to the annexation] sends the signal to President Putin that he can be even more ambitious and aggressive in his military intervention in Ukraine."

When a Western consensus finally emerged, Russia was slapped with sanctions and condemned in the United Nations . Not only was the G8 summit in Sochi canceled that year, Russia had to face the ignominy of being kicked out of the group.

The international response was tough, but apparently not tough enough; some months later, Russian-backed rebels invaded the Donbas region in eastern Ukraine, triggering even more sanctions

The biting sanctions are still in place - not a good thing for a sputtering Russian economy . But five years later, President Trump seems ready to welcome Russia back in the club of the world's most powerful nations.

Ahead of the G7 summit in France this weekend, Trump said , "I think it's much more appropriate to have Russia in" the group, adding, "If somebody would make that motion, I would certainly be disposed to think about it very favorably."

Sen. McCain must be rolling in his grave.

A Non-Summit in The Making

It is almost impossible to predict what Trump will do at the G7 this weekend. Last year the disrupter-in-chief left allies flabbergasted when he withheld his imprimatur from the meeting's final statement and then went on to insult his host, Canadian Prime Minister Justin Trudeau.

Expect more fireworks this weekend - especially after Trump escalated the trade war with China and ordered US companies to "start looking for an alternative to China." French President Emmanuel Macron is already playing defense, saying the summit will not produce a final communique, due to deep divisions among leaders on such issues as the reinstatement of Russia and climate change.

While Trump may be leaning toward inviting Russia back into the club, little has changed to warrant this. It appears sanctions alone have not been enough to curb illegal Russian activity. The US intelligence community concluded Moscow interfered in the 2016 US elections , and there is scant evidence to suggest that a charm offensive from the international community would lead to better behavior.

"President Macron and Chancellor Merkel have made clear that any discussion of Russia's reinstatement in the G8 requires movement by Moscow on implementation of Minsk," former NATO Deputy Secretary General and US ambassador to Russia, Alexander Vershbow, told me. "Trump may be indifferent to Russia's violation of Ukraine's sovereignty and Kyiv's freedom to pursue its Euro-Atlantic aspirations, but members of his administration and the Congress will hopefully continue to check his inclination to throw Ukraine under the bus for the sake of an empty partnership with his friend Putin."

Even though Britain's new Prime Minister Boris Johnson has voiced opposition to Russia coming back into the G7, one never knows what his impulsive behavior and flourishing bromance with Trump could bring.

Zelensky has long called for peace in the Donbas, even before his shock election victory in April. Already, Zelensky has held at least two phone conversations with Putin, something his predecessor, Petro Poroshenko, stopped doing long ago. While he has called for the return of Crimea he very likely realizes that Russia, having sunk millions into infrastructure to integrate the peninsula - including a bridge over the Kerch Strait, has no intention of ever relinquishing it.

It may be a long way off before Russia is allowed back into the G7, but Russia could be motivated to compromise in order to have sanctions eased. For that to happen, Western leaders would probably need to see a withdrawal from eastern Ukraine, the release of the Ukrainian seamen captured by Russia last November and the cessation of the harassment of shipping in the Sea of Azov , which has hit the Ukrainian economy hard.

Trump and Putin

Trump and Putin share one main trait: they are both unpredictable and don't like being pushed around. And some suggest the Russian leader is doing perfectly fine outside the G7, given that Putin has never prioritized warm ties with the West.

If that's the case, Trump could be doing Putin's bidding in vain.

Said Vershbow: "Russia shows no desire to rejoin the G8, since it never wielded any influence in the group and is no longer interested in any of the forms of Western integration pursued by both Russia and the West after the end of the Cold War. Moreover, Russia's middle-weight economy and disruptive behavior around the world make it of dubious value to the G7 partners."

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Finally, what Trump wants may not be what he gets. He still has hawks in his own party and opposition in Congress when it comes to easing up on Russia. It was just a little over two years, that Trump, facing overwhelming partisan support, approved fresh sanctions on Russia that were partly in response to its annexation of Crimea.

Bad behavior should never be rewarded. By allowing Russia back into the G7 while it continues to disrupt the rules based international order, Western leaders would be setting a bad precedent. What kind of signal would it send to other strongmen such as President Xi Jinping in China, the embattled Nicolas Maduro in Venezuela, or President Bashar al-Assad in Syria? A red line needs to be drawn somewhere.