"It doesn't fix what's really broken about our current system," he said. "And added to that, has incredibly indefensible partisan consequences." A Gallup survey taken earlier this month found that 63 percent of Americans, including more than six in 10 Republicans, Democrats and independents, support "doing away with the Electoral College and basing the election of the president on the total vote cast throughout the nation."

Were the changes to get passed and signed into law, they could face legal challenges. Columbia University election law expert Nathaniel Persily said the Virginia law could potentially be challenged under the Voting Rights Act, with an argument that the move discriminates against African-Americans. He added that it could be challenged in any state with a claim that it violates the equal protection clause of the 14th amendment, and could also be challenged under the constitutions of the various states.

Persily acknowledged, however, that the courts have not struck down the system in the two states where it is already in place. "You have to think of a legal theory that would strike this down but not strike down Maine and Nebraska," said Persily. "The question is, does the motivation make a difference?" He said the motivation argument could be made in the context of other recent moves by Republicans, including the voter ID and early vote changes seemingly designed to boost the GOP.

No matter how it played out, he added, passage of such laws would be "tantamount to a declaration of political nuclear war."