Story highlights Michael Flynn's resignation is another moment of vulnerability for the new president, whose praise for Putin's Russia has put him at odds with the GOP majority on Capitol Hill, writes Julian Zelizer

Zelizer says it could fuel investigations of the role of Russia in the election

(CNN) Michael T. Flynn's resignation is the second major blow to the Trump administration within the span of a week.

After the courts stopped the President's executive order halting admission of refugees, his national security adviser is forced to step down amid revelations of his discussions with Russian officials following the election. The resignation comes in the wake of mixed signals from the White House about what would happen to Flynn

It is not a total surprise that Flynn is the first major member of the administration to fall from power. He has always been one of the most controversial figures in Trump's inner circle. A national security adviser whose views were seen as far outside the mainstream, Flynn bought into conspiracy theories and made anti-Islamic statements.

When he joined the chant of "lock her up" against Hillary Clinton at the Republican National Convention he made it clear that this military official had turned into a rabid partisan attack dog. Many national security experts shuddered to think that Flynn, with his outlandish views, would be the last person in the room when President Trump was making decisions about war and peace.

Now that he is gone the question is whether this turns into something bigger. The problem with Flynn was not simply his own actions but his part in a broader story that has been nagging Trump since the campaign -- why is he so sympathetic to Russia and what kinds of connections have existed, if any, between his inner circle and a foreign government that aggressively intervened in the 2016 election.

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