Plurality Good Enough to Maintain Two-Party System

Some people think that direct election of the president should be conditioned on the winner getting at least 40% of the national vote. In his 1971 book "Reform and Continuity" Alexander Bickel argued persuasively that such a requirement would undermine the two-party system.

It follows that if states chose to allocate electors based on who won the national popular vote, regardless of the size of the plurality, then the two-party system would be strengthened, or at least in no way undercut.