Trump says Michael Flynn got security clearance because 'Obama didn't vet' him -- Business Insider:

President Donald Trump told Fox News on Friday that Michael Flynn was "already approved by the Obama administration at the highest level" when he was hired to serve as national security adviser in January. Flynn, who headed the Defense Intelligence Agency from 2012 to 2014, came under renewed scrutiny earlier this week when the House Oversight Committee revealed that he did not disclose his payments from Russia's state-owned news agency, Russia Today, when he was renewing his security clearance...
http://www.businessinsider.com/trump-obama-michael-flynn-security-clearance-2017-4