If states can exercise this power in the absence of a compact, then why don't they? Are they afraid of throwing their vote away if they independently chose to award their electoral college votes to the winner of the national popular vote?
-PJ
Because the compact would become effective only when it encompasses states collectively possessing a majority of the electoral votes, the presidential candidate receiving the most popular votes in all 50 states and the District of Columbia would be guaranteed enough electoral votes in the Electoral College to be elected to the Presidency.
No single state would ever be likely to unilaterally enact a law awarding its electoral votes to the nationwide winner. For one thing, such an action would give the voters of all the other states a voice in the selection of the state’s own presidential electors, while not giving the enacting state the benefit of a voice in the selection of presidential electors in other states. Moreover, enactment of such a law in a single state would encourage the presidential candidates to ignore the enacting state. Such unilateral action would not guarantee achievement of the goal of nationwide popular election of the President.