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Flynn has long-standing ties to Russia, most notably he received payment to attend a gala event for Russia Today, a Russian propaganda outlet. On that occasion, he dined with Russian President Vladimir Putin.
The Wall Street Journal reported in January that US counterintelligence agents have investigated Flynn's ties to Russia. Recently a group of top Democratic lawmakers urged the Department of
Throughout his campaign and presidency, Trump has repeatedly questioned the NATO alliance and the US's adversarial relationship with Russia.
Despite that, the US continues to back Montenegro's bid to join NATO. The US Senate Foreign Relations Committee has backed Montenegro's bid for over a year. During this time, the small Balkan nation faced increasing pressure from Russia - including a failed coup in October 2016, that may be tied back to Moscow.
A special prosecutor in Montenegro said that Russian nationalists tried to sway the country's October election with a plot to kill the Western-leaning Prime Minister Milo Djukanovic.
"The organizers of this criminal group were nationalists from Russia whose initial premise and the conclusion was that the government in Montenegro led my Milo Djukanovic cannot be changed in the election and that it should be toppled by force," Milivoje Katnic, special prosecutor for organized crime in Montenegro, said at the time.
NATO
Flynn's backing of Montenegro's entrance into NATO would seemingly fly in the face of Trump's proposal to try and befriend Russia, as Russia sees NATO expansion as aggression against its interests. Jorge Benitez, a senior fellow and NATO expert at the Atlantic Council, told Politico that "No NATO candidate country has ever faced such a dire attack or threat in the process of finishing its membership into the alliance."
However, Flynn is not alone among Trump appointees in striking a more hawking tone towards Moscow. UN Ambassador Nikki Haley also signaled a hawkish approach, saying that "the dire situation in eastern Ukraine is one that demands clear and strong condemnation of Russian actions." Russia officially denies a military presence in Eastern Ukraine, where fighting has recently reignited.
Before Montenegro can join NATO, it's ascension bid must be approved by all 28 current NATO states and two-thirds of the US Senate.