“This constant using them as punching bags is likely to backfire because their own domestic audiences will expect them to more and more stand up to our President Trump,” she said on “ Power Lunch .”

While the president may have a point on spending, “weaponizing the burden-sharing theme” is not the way to go about it, James told CNBC on Wednesday.

As the NATO summit opened in Brussels, Belgium, on Wednesday, Trump slammed Germany as being “totally controlled” by Russia and went after leaders for not contributing more to defense spending.

President Donald Trump ’s tactics towards NATO allies are “way, way over the top,” said Deborah Lee James, former secretary of the Air Force.

President Donald Trump and Britain's Prime Minister Theresa May talk as NATO leaders pose for a family photo at the start of the NATO summit in Brussels, Belgium July 11, 2018.

On Wednesday, Trump insisted allies “must pay” 2 percent of their country’s gross domestic product “immediately.”

The current agreed-upon standards call for allies to gradually increase spending to 2 percent by 2024. Right now, only five out of the 29 nations meet the 2 percent NATO guideline.

Trump tweet

Earlier in the day, the White House confirmed that Trump also demanded that agreed-upon level be doubled to 4 percent of GDP.

Meanwhile, Trump’s accusation that Germany was “controlled by” Russia was based on oil and gas deals he says have given Moscow far too much influence over the continent’s largest economy.

“Germany is totally controlled by Russia … They will be getting between 60 and 70 percent of their energy from Russia and a new pipeline, and you tell me if that is appropriate, because I think it's not,” Trump said, before criticizing Berlin's failure to significantly increase defense spending.

Gen. Wesley Clark, former NATO Supreme Allied Commander, told “Power Lunch” that criticism is a big overstatement.

“To say that they’re controlled by Russia is like saying that the United States is controlled by China because China buys American bonds and holds a lot of American debt,” Clark said.

“It plays well to President Trump’s domestic base and it alienates allies in Europe who understand what the real situation is.”

Clark, who retired in 2000 after rising to the rank of four-star general, said NATO has been useful in providing stability and security in Europe since World War II.

“It’s benefited us just as much if not more so than the Europeans,” he said. “It’s not a matter of transactions. It’s not a matter of dollar for dollar. It’s a matter of building an Atlantic community in which everybody can trust and work together and grow. That’s what NATO does.”

In fact, he sees a possible opening for Russia in Eastern European countries thanks to the “discord” and “confusion” inside NATO, which encourages leaders to stand up and say the U.S. is not reliable.

“That opens the way for Russia’s corruption and other Russian influences in these countries that are harmful to the countries, harmful to good business practices, undercut the European Union as well, and really it undercuts the whole trans-Atlantic security we’re setting up,” he said.

Across the pond, there was agreement from Lord William Hague, former U.K. foreign secretary. He told CNBC’s Wilfred Frost Wednesday that while the U.S. has a point about defense spending, that is not the only aspect of NATO.

“It would be a great concern if this meeting ended in acrimony, because this is a vital alliance,” Hague said.

“The United States in the 20th century was twice embroiled in a catastrophic war here in Europe because of a breakdown of European security, and an alliance that maintains European security is fundamentally in the interests of the United States, almost irrespective of what the individual members spend,” he added.

For James, she’s concerned about the juxtaposition between Trump’s behavior at the NATO summit and his upcoming meeting with Russian President Vladimir Putin.

“My great fear is that in contrast to this very, very tense combative summit with our closest allies on Earth, our president may go into a discussion which turns out to be very chummy with Vladimir Putin,” she noted. “Russia, of course, is one of the top threats that we see to our security interests.”

— CNBC’s Sam Meredith contributed to this report.