With two of the three most recent presidents entering the White House after losing the popular vote, activists have intensified their efforts to eliminate, change or bypass the Electoral College, the system in which political party leaders nominate electors in each state who vote to select the president based on how their state voted. Electoral College critics, who tend to be Democrats, are pressuring states to join an interstate compact that would require the states' electors to vote for the winner of the national popular vote, regardless of the results in their individual state. Fifteen states and the District of Columbia — which together control 196 electoral votes — have joined the compact, which would take effect only if enough states sign on to control the 270 votes required to elect a president. Polls show most Americans prefer that presidents be elected by popular vote. But Electoral College supporters, who tend to be Republicans, say scrapping the college would reduce the political power of small states and rural areas.