Senator John McCain is right. Vladimir Putin is “the premier and most important threat, more so than ISIS.”

To be sure, ISIS represents a great threat. Fortunately, the threat is slowly, but surely being brought under control.

The Russian threat, however, is not under control, and Vladimir Putin is actively undermining American leadership abroad, the integrity of our political system, and the sovereignty of our allies.

Further, the Trump administration’s unprecedented relationship with Putin has worsened the threat posed by Russia globally.

Trump’s recent foreign trip to Europe only exacerbated the threat as well. By unmistakably failing to endorse Article 5 of the NATO treaty in his address to our NATO allies, the president swung the trip unequivocally to Putin’s advantage.

Until recently, the West has largely downplayed Russia’s military might, minimizing the capabilities of their outdated equipment and poor organization.

Over the past few years, however, the Russian government has undertaken one of the most rapid and aggressive efforts in the world to overhaul their military, including a $720 billion initiative aimed at modernizing their full arsenal of weaponry by 2020.

While it is difficult to foresee a direct conflict between Russia and the United States, Russian involvement in Syria demonstrates Putin’s willingness to support his political goals with military strength.

Russia’s heavy-handed support of Bashar al-Assad demonstrates that Putin stands ready to insert himself into hot, internal conflicts on the side of murderous despots, like Assad, as a means of dividing the West.

Putin has stepped up his aggression in Ukraine. In just the past year, he has mobilized a full 40,000 troops on the Russian-Ukrainian border, in what American officials fear may be an invasion in the making. He continues to send menacing signals in Eastern Europe, and his aggressive campaign of cyberwarfare internationally continues.

Under Putin’s leadership, Russia remains anti-Western, anti-democratic, and unpredictable. Even more troublingly, his authoritarian model has attracted legions of admirers, including in the West. Not only does the Russian strongman president have his defenders—including Donald Trump—but researchers in Western countries have noted a growing public tolerance for, and even admiration of, authoritarian brands of leadership.

Petro-politics are also central to Putin’s efforts to both undermine and evade international sanctions. Most recently, Putin’s plot to transport Syrian crude oil through the Caribbean was uncovered. Putin’s planned scheme involved selling Syrian oil through Venezuelan front companies, which would subsequently deliver the oil to the U.S. market.

Meanwhile, as American leadership retreats from the geopolitical war against Russia, Vladimir Putin continues to manipulate the European continent to his advantage on all sides and represents the greatest threat to democracy in a generation.

Make no mistake, as Senator McCain rightfully warns, Putin is assembling a menacing, new global order and it poses a much greater threat than ISIS ever could.