McCain argued against the nomination during the meeting of the Senate Foreign Relations Committee on Tuesday, which went on to approve Tsunis by a majority of 12 to six.
"The question is whether . . . [Tsunis] will embarrass the United States of America while serving as our representative," McCain said.
He reminded the committee's members that Tsunis had referred to "the president" of Norway in his January 16 hearing and attacked the anti-immigration Progress Party, which has seven ministers in government, as "fringe elements" that "spew their hatred".
"There is no president -- it's a constitutional monarchy," McCain pointed out, before adding: "He talks about a faction within the government as condemned by the government."
Chris Murphy, a Democrat senator, defended Tsunis, saying that he had displayed "fairly impressive and wide-ranging knowledge" of Norway in a previous hearing before January's disastrous performance.
The Greek-American hotel millionaire last week told The Local how keen he was to show Norwegians his true personality.
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"As you can imagine, the day when I am able to make a second impression cannot come soon enough," he said.
The full US Senate’s final vote on Tsunis’ nomination has not yet been scheduled.