As this chart shows, money does not enter politics equally from both ends of the political spectrum:

Most of the policy preferences supported by the biggest funders on this list run counter to the wishes of the majority of Americans. Gun control stands out as a clear illustration. Money cannot be kept out of politics (although the Supreme Court has done the country no favor by increasing its importance). But the current presidential selection system increases money's leverage by causing the winner of the election to be chosen from a handful of swing states, where the dollar-to-voter ratio rises to dizzying levels. If money had to persuade not just a hundred thousand voters in swing states but up to 200 million voters, then its power over the outcome would be diminished. 

Seeking federal legislation to constrain the role of money is hopeless, even if the Democrats controlled both houses, given the make-up of the Supreme Court and its unfortunate precedents. But moving to the national popular vote as the means to choose the president is quite possible. If the amount of money spent by any of the groups in the chart were dedicated to legislation awarding electors to the national vote winner, then this reform would be effective for the 2020 election, and the role of money on choosing the next president would shrink far more radically than any other feasible method could accomplish.