Majority Leader Mitch McConnell (R-Ky.) took to the Senate floor Monday to angrily defend himself against allegations that he is doing the bidding of Russian President Vladimir Putin by blocking a series of election security bills proposed by Democrats.

"Last week I stopped Democrats from passing an election law bill through the Senate by unanimous consent, a bill that was so partisan that it only received one Republican vote over in the House. My Democratic friends asked for unanimous consent to pass a bill that everyone knows isn't unanimous and never will be unanimous. So I objected. ... Over the last several days I was called unpatriotic, un-American, and essentially treasonous by a couple of left-wing pundits on the basis of bold-faced lies. I was accused of aiding and abetting the very man I've singled out as an adversary and opposed for nearly 20 years, Vladimir Putin."

The backdrop: In the 24 hours after former special counsel Robert Mueller testified about Russian interference in the 2016 election, McConnell and several other Republicans blocked election security bills from being passed by unanimous consent on the grounds that they were partisan, and that the GOP has already take steps to improve security for the upcoming election.

Democrats and many in the media responded by questioning whether McConnell's actions would effectively amount to an invitation for Russia to interfere again in 2020. MSNBC host Joe Scarborough dubbed McConnell "Moscow Mitch," while Washington Post columnist Dana Milibank wrote a scathing op-ed accusing him of being a "Russian asset." In the op-ed, Milibank noted that McConnell had blocked attempts to pass the following bills:

A Democratic bill passed in the House that would "direct $600 million in election assistance to states and require backup paper ballots."

"A bipartisan bill requiring Facebook, Google and other Internet companies to disclose purchasers of political ads, to identify foreign influence."

"A bipartisan bill to ease cooperation between state election officials and federal intelligence agencies."

"A bipartisan bill imposing sanctions on any entity that attacks a U.S. election."

"A bipartisan bill with severe new sanctions on Russia for its cybercrimes."

The big picture: McConnell maintains that he takes seriously the threat of election interference, and that Republicans have already taken steps to strengthen security. But just last week, FBI Director Christopher Wray testified that the Russians are "absolutely intent on trying to interfere with our elections," and that the U.S. has not done enough to deter the Kremlin from repeating what it did in 2016.

Go deeper: Senate Intel report finds Russians attempted to intrude in all 50 states in 2016