Presidents often award diplomatic posts to campaign donors and fundraisers, but Sen. Marco Rubio, R-Fla., suspects that Obama's choice of ambassador to Argentina -- a man who bundled more than $500,000 for President Obama's 2012 re-election campaign, but who has never been to the country -- is in over his head.

"Have you been to Argentina?" Rubio asked Noah Mamet during a Senate Foreign Relations Committee hearing Thursday.

"I haven't had the opportunity yet to be there," Mamet replied. "I've traveled pretty extensively around the world, but I haven't yet had a chance [to visit Argentina]."

Rubio implied that Argentina is too important a country to be entrusted to a campaign donor rather than a professional, as is the case with some other diplomatic posts. "I don't view this appointment as one — I think this is a very significant post," he said.

Under Ronald Reagan, both Bushes and Bill Clinton, U.S. ambassadors to Argentina were career Foreign Service officers -- professional diplomats. But Obama's previous choice, current Ambassador Vilma Soccorro Martinez, is a civil rights lawyer with no previous foreign diplomatic experience. The choice of Mamet is likely to revitalize the perception in Latin America that Obama doesn't care much about the region.

Rubio meanwhile spent the rest of his exchange explaining to Mamet the difficulty of the job he seeks, pressing the nominee on whether the Argentinean government even qualifies as an ally anymore. Mamet said Argentina's government is an ally.

"This is the most unique ally, I think, we have in the world then," Rubio replied. "Argentina is an ally that doesn't pay American bondholders the money they owe them, doesn't cooperate with our military," and has joined with Iran to appoint a "truth commission" to reinvestigate the 1994 terrorist attack on a Jewish community center in Buenos Aires, which an Argentinean special prosecutor had previously concluded was authorized by the Iranian government.

"These are, in my opinion, not the actions of an ally," Rubio said.

When asked earlier in the exchange about the new "truth commission," Mamet replied, "I think mature democracies can disagree and do it very directly and forcefully when needed — either publicly or privately."

Rubio warned Mamet that Argentina might have an economic collapse in the near future, adding that he thinks the country is listing towards an authoritarian regime.

"The anti-democratic direction that Argentina is going reminds me a lot more of Ecuador, and Bolivia, and Venezuela than it does of Mexico and Chile and Peru and Colombia," Rubio said. "Those are allies. I think the Argentinean government needs to make up its mind what they are toward the United States."

Buzzfeed reported Mamet's nomination angered Democratic donors. " Democratic Party donors complain privately that Mamet unfairly leveraged his clients' work for his own political gain and benefited from a close personal relationship with President Obama's campaign manager, Jim Messina," Ruby Cramer wrote.