When he was president of Estonia, Toomas Hendrik Ilves did not hold back in sounding alarms about Russia’s increasingly provocative military moves in Europe, and condemning Vladimir Putin’s defiance of international accords.

Now, Ilves continues to closely track Russia and Putin, and remains committed to warning Europe and the United States not to let down their guard or underestimate the nation that shares borders with more than 12 countries.

Earlier this month, for instance, Ilves was in Washington D.C. to testify before the U.S. House Foreign Affairs Committee in a hearing about Russian attempts to undermine democratic institutions and undermine NATO. He was one of only four experts witnesses called before the committee. Days later, Ilves testified before the Senate Judiciary Subcommittee on Crime and Terrorism.

Ilves, who is a visiting fellow at Stanford University's Center for International Security and Cooperation, has a central warning – that Russia wants to sabotage democracies and that military provocations – though worthy of concern and vigilance – may be secondary to Russia’s determination and capacity to sway elections and disseminate propaganda through cyberspace.

Russia is engaging in asymmetrical warfare. It’s asymmetrical because they can do things to democracies that democracies can’t do back to an authoritarian government. — Toomas Ilves, past president of Estonia

“Russia has had very aggressive military exercises,” Ilves told Fox News. “They’ve practiced mock nuclear attacks on Warsaw. Russian bombers practiced attacking strategic military targets in Sweden. The military aggression gets everybody nervous. We’re dealing with rogue behavior on the part of a major nuclear power.”

And while such concerns on the part of the European Union and the Baltic States, among others, certainly is valid, Ilves said, the most immediate menace by Russia is its increasingly bold efforts to hack systems and interfere with elections.

“I’m more concerned about their intentions to influence elections,” Ilves said, “it’s much cheaper to influence elections than it is to go to war.”

“Russia is engaging in asymmetrical warfare,” he added. “It’s asymmetrical because they can do things to democracies that democracies can’t do back to an authoritarian government.”

Ilves says elections in France and Germany this year are of particular concern because of the possibility that Russia will attempt to influence the outcome.

Aides to French presidential candidate Emmanuel Macron, an independent centrist, accused Russian groups of trying to hurt his campaign with social media posts accusing the married contender of being gay.

Putin, who supports candidate Marine Le Pen for her anti-European Union stance, has denied that Russia is attempting to meddle in the French elections.

“They hack email and publish embarrassing articles,” Ilves said. “Russians don’t like Macron, they don’t want him being president. Macron is seen as a unifying figure in the European Union holding sanctions [against Russia].”

In Germany, President Angela Merkel is expected to win re-election. But others running for legislative seats could slow or hurt her efforts to advance policies or proposals, and that would be an area where Russian interference in the elections would affect German government actions, experts say.

“In Germany, concerns are great” about Russia’s intentions, Ilves said.

The presidential elections in both nations, he noted, could produce a “very big change in Europe.”

“Just yesterday, yet another report from the European intelligence agency said that once again the Russians have hacked into the Parliament,” he said. “And the day before yesterday, the Swedish intelligence agency published a report on Russia attempts to influence the political scene in Sweden.”

Just one year after Ilves became president in 2006, Estonia experienced a Russian cyberattack, making the former Estonian leader an unwitting expert on the issue.

“The lesson for everyone is not to be naïve” when it comes to Russia and Putin, he said.

“The watershed moment was Russia’s invasion of Georgia in 2008,” Ilves said, saying it led to the pattern of Russia’s brazen “overturning of fundamental principles we’ve all been living with.”

With Putin, Ilves said, “You can’t say ‘He would never do that,’ because he has done what we have said he would never do.”