They are both populists with incomparable egos -- maybe except in relation to each other. They both promise to restore their countries' lost glory -- and go on quite a bit about the threat of external enemies.
Mysteries surround their looks -- How does his hair do that? How does he look so young? And both, at times, seem to sport a bit of an orange tan.
Peter Pomerantsev, author of Nothing Is True and Everything Is Possible, an absurdist account of working as a reality TV producer in Putin’s Russia, classified both men as "buffoonist TV populists" whose true beliefs are hard to determine.
"You can't pin Trump down ideologically -- that's a lot like Putin," Pomerantsev told Mashable. "Trump is not classically left or right wing...He's sort of a capitalist--socialist."
And like Putin, he is "anti-elite" as evidenced by his recent jabs at "hedge fund guys" on Wall Street, Pomerantsev added.
David Ignatius posed the question "Is Donald Trump an American Putin?" in a recent Washington Post op-ed, listing the many similarities while also noting one difference: "Trump is more nakedly self-promoting than Putin, with a vanity and braggadocio that would embarrass a Russian (or, indeed, almost anyone)."
Russia observers and journalists have also noticed some echoes.
You know how you've been in Russia for too long? You can't watch Trump. At all. BECAUSE YOU'VE HEARD IT ALL BEFORE FROM PUTIN.— Natalia Antonova (@NataliaAntonova) August 29, 2015
Like Putin, Trump understands the importance of performing for the media. He might not rip his shirt off and gallop into the sunset on the back of a stallion as part of a well-orchestrated PR stunt, but he is a seasoned reality TV star who knows how to work every camera angle.
Trump's campaign slogan, "Make America Great Again," may be a borrowed line from Ronald Reagan's 1980 acceptance speech, as Ignatius noted, but it also sounds a lot like Putin's refrain to restore the greatness of Russia.
"We have no victories," Trump said in a recent Meet The Press appearance. "As a country, we don't have victories anymore. And it's very sad."
"Russia is in the midst of one of the most difficult periods in its history," Putin said in a famous 1999 speech. "We are running out of time for removing this threat...We need coordinated creative work. Nobody will do it for us."
More recently, he blasted America for "attempts to create a unipolar world." Trump, of course, is suspicious of China.
Time will tell if Trump can remain atop the polls or if his campaign will prove to be a flash in the pan. But should he fail at his bid for the White House, perhaps there's another job he could fill.
"Putin is looking for someone to hand [his] power to, and he has no contacts in Russia who doesn't threaten him," Pomerantsev said. "If Trump fails in the U.S., maybe he can become head of Russia, and bring Russia back to greatness."
After all, Trump did say he'd get on "very well" with Putin.