One person, one vote, with equal effect. On its surface, proportional democratic representation sounds like a wonderful, common-sense, plan. Why not have true voting equality for each individual?
In reality, eliminating the Electoral College would lead to certain disaster.* If we want to live in peace, it is essential to maintain respect for local political culture, local legal diversity, and local experimentation.
The federal United States government is similar to the worldwide United Nations in that both exist to serve constituent members. Notably, such constituent members are states and countries, respectively, not individuals.
Setting aside the question of desirability, imagine if the U.N. becomes something more akin to the federal government, i.e., with teeth to enforce its decrees. Even if each country loses political power to a global U.N. government, it would be deeply immoral to replace the current, country-based U.N. voting system with proportional representation. There is no moral basis to justify more populous countries having the political power to demand that their own cultural norms and preferences be legally enforced in smaller countries. That would be the worst sort of "might makes right" imperialism.
Further, if two or three populous countries could outvote all other individual, diverse countries, the U.N. would lose any peacekeeping purpose it might otherwise have between and among voluntary constituent countries. Without a voice at the table, what motive would smaller countries have to remain constituent members? Instead, they would understandably want to struggle for secession, and, if necessary, fight for their independence.
Just as three countries should not determine global politics, neither should three cities determine the U.S. federal political landscape. The reality is that people are diverse not only on an individual basis, but on a geographic, community-wide one. Different regions have different cultures, languages, interests, and values. Beyond such human-oriented differences, diversity in the region itself - in resources, geography, size, etc. - often mean that the people living in a particular location have unique needs. Large-scale, top-down, one-size-fits-all laws are almost certain to have a disproportionate negative effect in particular geographical areas. Removing local governance and problem-solving is therefore fundamentally unjust. So long as each locality respects individual rights (including the right to leave), local diversity should be respected.
This point is particularly consequential given that we cannot currently rely on those entrusted to defend, execute, and interpret the Constitution to adequately protect individual rights and liberties from majoritarian rule. If our Constitutional Republic were stronger, perhaps eliminating the Electoral College would not be quite such a terrifying and grave prospect. Then again, if we did not have such immense unConstitutional government overreach, the new political push to eliminate the Electoral College likely would not exist in the first place. When government is too large, that creates a high risk, high reward situation, where gaining or losing political control means far too much. It is hardly surprising that unhealthy power grabs and corruption become more common in that scenario.
Given the current fragility of our Constitution, eliminating the Electoral College could very well result in gross civil liberties violations, serious state movements for secession, and even Civil War. To keep the peace, which is intimately tied to individual rights and liberties, liberty-minded individuals should carefully protect and defend the Constitution - including the Constitutional text pertaining to the Electoral College.
Fortunately, it is extremely difficult to amend the Constitution. Although Constitutional interpretation has significantly weakened Constitutional limitations on government power, the text itself remains largely impervious to temporary political whims. The Constitution will almost certainly weather this most recent political storm, with these ill-considered schemes relegated to historical footnotes.
*Caveat - all of the above holds true at this stage in human history. It is possible that these geographical differences between communities will become less pronounced. Currently, however, geographical political differences in America are becoming more distinct, not less.