Voters want that guarantee, that even if they were on the losing side, their vote actually was directly and equally counted and mattered to their candidate. Most Americans think it's a bad thing for the candidate with the most popular votes to lose. We don't allow this in any other election in our representative republic.
Support for a national popular vote is strong among Republicans, Democrats, and Independent voters, as well as every demographic group in virtually every state surveyed in recent polls in recent closely divided Battleground states: CO – 68%, FL – 78%, IA 75%, MI – 73%, MO – 70%, NH – 69%, NV – 72%, NM– 76%, NC – 74%, OH – 70%, PA – 78%, VA – 74%, and WI – 71%; in Small states (3 to 5 electoral votes): AK – 70%, DC – 76%, DE – 75%, ID – 77%, ME – 77%, MT – 72%, NE 74%, NH – 69%, NV – 72%, NM – 76%, OK – 81%, RI – 74%, SD – 71%, UT – 70%, VT – 75%, WV – 81%, and WY – 69%; in Southern and Border states: AR – 80%, KY- 80%, MS – 77%, MO – 70%, NC – 74%, OK – 81%, SC – 71%, TN – 83%, VA – 74%, and WV – 81%; and in other states polled: AZ – 67%, CA – 70%, CT – 74%, MA – 73%, MN – 75%, NY – 79%, OR – 76%, and WA – 77%.
Even if all 50 states and DC used a proportional method, the presidency would not be guaranteed to the candidate with the most votes. Voters do not want any possibility of an electoral vote tie leaving Congress (with less than 10% approval rating now) to decide a presidential election, with each state having one vote, (with equally divided states being unable to cast a vote).