Republican lawmakers in several swing states want to replace their winner-take-all system of allocating presidential electoral votes with a "proportional" system. Their proposals, however, are not for truly proportional allocation but for winner-take-all divvying by congressional district.
As The Times notes, under this system, Mitt Romney would have received nine of Virginia's 13 electors. President Obama, who won 51.2% of the statewide vote, would have had barely 30% of the electors. This does not meet any standard of proportionality.
Even the makeup of the House of Representatives, which is determined by congressional districts, is not proportional. Although Democrats won the most House votes in 2012, Republicans retained their majority.