NEW YORK (TheStreet) -- U.S. President Barack Obama's foreign policy has the world "thoroughly confused," according to Ian Bremmer in his new book Superpower.

Bremmer said the countries that "have historically been aligned with us are actually orienting in ways that are really going to fragment the global system long term. That's unavoidably going to have a big impact on the global economy."

He is not impressed by the U.S. relationship with Russia. Russian President Vladimir Putin is the single most powerful person in the world, in Bremmer's view, and despite a number of U.S. threats for Russia's actions in the Ukraine and Syria, there's been little to show for it.

"He's not going to change," Bremmer said of Putin, "so as a consequence we are seeing escalation. We are seeing Russia move toward China and we see them flexing their muscles military and engaging in cyber-attacks against us. This can only get worse."

The U.S. relationship with China has been better managed, he added. But as China becomes the world's largest economy, America's former economic allies and global corporations will move toward the Chinese model, leaving the U.S. behind. Meanwhile, Bremmer is bullish on a potential deal between the U.S. and Iran, despite objections from America's traditional allies in the Middle East.

"They might not like it but there is nothing they can really do about it," said Bremmer. "Ultimately, [China is] a larger market."

Bremmer said Democrat forerunner and former secretary of state Hillary Rodham Clinton has the most foreign policy experience but has backed away from her previous positions in Iraq and Libya, among other places, so Bremmer wonders about her authenticity.

On the Republican side, Bremmer said Rand Paul has the most coherent foreign policy strategy because of his isolationist stance. Marco Rubio, at the other end of the spectrum, favors an "indispensable" America that will defend international incursions anywhere on the globe.

"We really do have a debate in 2016 in a way we didn't and should have had in 2012," he concluded.