It may surprise some Americans to learn that Mexico is an especially high-value target.

The Putin-Patrushev strategy in the Americas is more than a tit-for-tat effort to counteract U.S. support for democracy in Europe. The destabilization of Western-style democracy in the region is central to the pair’s shared dream of restoring the global power of Mother Russia.

It’s reasonable to assume that Mr. Putin’s aspirations for a new empire aren’t shared by everyone in the Russian power structure. His costly assault on Ukraine has been a flop, either because he mismanaged it or because he underestimated the enemy—or both. In any case, it doesn’t project strength.

If Mr. Putin’s star is falling, the colonial outposts built and nurtured by Mr. Patrushev—in Cuba, Venezuela, Colombia, Nicaragua and, yes, Mexico, among others—could be at risk. Conversely, Putin staying-power implies continued clear sailing for Agent Patrushev.

Messrs. Putin and Patrushev have a relationship dating to the 1970s, when both were KGB agents. From 1999 to 2008 Mr. Patrushev was the director of the Russian intelligence agency known as the FSB—the restructured KGB. He is credited with bringing Mr. Putin to power and has been called the most likely successor if the boss retires.

For now Mr. Patrushev serves as Mr. Putin’s top spook, spanning the globe to help put down color revolutions, throw elections and challenge the unipolar multilateral system that has taken root since the collapse of the Soviet Union.

Some of Mr. Patrushev’s work in the Americas is public, like his February consultations on security matters in Caracas with Venezuelan strongman Nicolás Maduro. Moscow is a major supplier of military equipment and services to Venezuela. The work of Wagner mercenaries is more behind-the-scenes. They’ve butted heads with the Russian military over Ukraine, but it’s doubtful they go abroad without the help of Russian embassies, where Mr. Patrushev holds considerable sway. In 2019 Wagner was brought into Venezuela as a regime enforcer and to train special forces. People familiar with the matter say Wagner also has provided security for the Venezuelan oil company.

In March Mr. Patrushev visited Raúl Castro in Cuba. Russia forgave $32 billion in Cuban debt in 2014 and in the decade since the Castro crime family and its associates have grown closer to Mr. Patrushev. In May Havana announced that it will send troops to train in Belarus to show solidarity with the Ukraine invasion. Last week Cuba and Russia announced they would work toward closer “technical military” cooperation.

Russia’s support for Nicaraguan despot Daniel Ortega is also an open secret. Less noticed is Moscow’s obsession with quietly fueling antidemocratic ideology elsewhere in the Americas—with little push-back from the U.S.

In 2020 Colombia kicked out two Russian spies who were reportedly working under diplomatic cover at the embassy in Bogotá. Colombia didn’t detail their transgressions, but Reuters said local media described their work as mining for “military intelligence and information about the energy industry and mineral commodities.” Neither reported to Mr. Patrushev’s bureaucracy directly, but both were intelligence agents under the broader control of Mr. Putin’s bestie.

In Colombia’s 2018 presidential election Russia allegedly engaged in a disinformation campaign in support of then-candidate Gustavo Petro. In the 2022 presidential election Russia again used disinformation and other dirty tricks to sow distrust in the democratic process and to help Mr. Petro, who won that contest. The U.S.-Colombia partnership of many years has come apart.

Russian intelligence activity in Mexico may be the most dangerous. In March 24, 2022, testimony before the Senate Armed Services Committee, Gen. Glen VanHerck, commander of U.S. Northern Command and North American Aerospace Defense Command, sounded the alarm. “There are actors who are very aggressive and active all across the” Northern Command, he said, “including the Bahamas and Mexico, China and Russia.” He noted that “the largest portion” of Russian intelligence personnel “in the world is in Mexico right now” and “they keep an eye very closely on their opportunities to have influence on U.S. opportunities and access.”

Earlier this year Mr. Patrushev predicted that Mexico would “sooner or later” recover the land it lost to the U.S. in 1848. I doubt that. But I have no doubt Mr. Patrushev will go to his grave still trying to make it happen.

*** O’Grady@wsj.com.