The electoral college vs. the popular vote: Could states do an end-run around the current system?

After Hillary Clinton won the popular vote but Donald Trump won the electoral college,activists renewed a push to revamp the system by which the presidency is awarded.

An article posted on the progressive website The Daily Kos described the effort this way:

"Eliminating the Electoral College does not even require a constitutional amendment. An effort known as The National Popular Vote Interstate Compact is an agreement among several U.S. states and the District of Columbia to award all their respective electoral votes to whichever presidential candidate wins the overall popular vote. Once states totaling 270 electoral votes join the compact -- which only requires passing state laws -- then the next presidential election will be determined the the popular vote, not the Electoral College."