If Donald Trump is elected president, some experts fear he could cause unnerving on U.S. allies and he could push for an American foreign policy that is more favorable to Russian President Vladimir Putin's goals and interests.
Trump's praise for Putin's "strong" leadership has already caused issues, said Evelyn Farkas, a former deputy assistant defense secretary for Russia, Ukraine, Eurasia in the Obama administration.
"He's already done damage to us vis-a-vis Russia as a candidate. I frankly shudder to think what he could to U.S. interests as commander-in-chief and president," Farkas, a senior fellow at the Atlantic Council, told NBC News.
Trump's effusive admiration for Putin, who Sen. Lindsey Graham, R-South Carolina, referred to on Thursday as "a thug, a dictator, an autocratic ruler who has his opposition killed in the streets of Russia" has baffled many, including some in his own party.
Nina Khrushcheva, a great-granddaughter of former Soviet Premier Nikita Khrushchev and a professor of international affairs at The New School, feels the Trump-Putin rapport could go one of two ways should Trump become president.
"It will supposedly be a very positive relationship," she told NBC News. "But since Putin and Trump in some ways are similar — that is, they say it like it is and really don't mind the consequences — it also is entirely possible and likely that that relationship will collapse quickly because one will insult the other and try to show each other who's the better man."