Who can deny that Russia, under President Vladimir Putin, has become a destructive force on the world stage? His barbaric assault on Ukraine, replete with war crimes, continues.

It would be morally unacceptable to allow him to attend the upcoming Group of 20 (G-20) Leaders’ Summit in Bali, Indonesia. In fact, Russia should be expelled from the G-20 altogether.

Diplomacy should always be attempted, but clearly it has proved useless in dealing with Mr. Putin’s Russia. Months of diplomacy between Western leaders and the Kremlin have done nothing to inhibit Russia’s barbaric aggression in Ukraine.

Mr. Putin’s intransigence warrants far broader consequences than individually sanctioning the Russian leader and his cronies. At this stage, Russia deserves to be treated as a pariah state. Yet, Indonesian President Joko Widodo recently revealed that Mr. Putin had assured him that he would attend the November summit meeting.

>>> The Biden Administration Should Unseat Russia from the Group of 20

The G-20 summit is billed as a political and economic forum at which leaders of the world’s 20 largest industrialized and emerging economies gather to discuss core international issues. Too often, these meetings produce little more than empty, diplomatic photo-op theater.

If the G-20 cannot summon the courage to make meaningful decisions—especially regarding such clear-cut issues as Russia’s invasion and rape of Ukraine—it will prove itself irrelevant to world affairs. In the run-up to the November summit, the U.S. and other willing members of the G-20 must make clear that Russia cannot be allowed to attend.

The collection of the 20 members—Argentina, Australia, Brazil, Britain, Canada, China, the European Union, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey and the United States—represents more than 80% of world gross domestic product, 75% of international trade, and 60% of the world population.

More than six months into Russia’s unprovoked invasion, the war seems nowhere close to ending. No immediate task is more important than acting with unity for Ukraine and its sovereignty.

As Heritage Foundation President Kevin Roberts put it: “America has clear national security and economic interests in a Europe that is stable and secure. Providing military resources to the people of Ukraine in their fight against Russia’s brutal invasion is a worthy cause that also advances those interests. The United States and its partners must ensure that Russia pays the highest possible cost for its invasion of Ukraine.”

President Biden must take necessary, proactive steps to ensure that Russia—a national security threat which breached international law with its invasion—is expelled from the G-20.

>>> War in Ukraine Shows Why Arms Trade Treaty Remains Bad Idea

On Sept. 5, Mr. Putin gave his approval to a new foreign policy doctrine based around the concept of a so-called “Russian World.” The 31-page “humanitarian policy” document declares that Russia should “protect, safeguard and advance the traditions and ideals of the Russian World.”

It presents a multitude of contrived reasons for invading Ukraine, such as the need to “de-Nazify” the country or to “liberate” its population from nationalists. Put bluntly, the “Russian World” is worthless propaganda that seeks to justify Mr. Putin’s outdated, imperialistic agenda.

Unsurprisingly, there is nothing “humanitarian” in the new doctrine either. Since Feb. 24, Russia has unambiguously demonstrated that it has no regard for human rights, other nations’ sovereignty and territorial integrity, or other nations’ right to determine their own future.

Mr. Putin clearly has imperialist ambitions, and has no compunction about using naked, violent aggression to expand his empire.

As long as his barbaric invasion of Ukraine grinds on, he deserves no seat at a gathering of supposedly civilized world leaders. Russia should be unseated from the G-20 before the heads of state descend on Bali this November.