Splitting electoral votes would increase campaigning activity and make every vote count even in historically "guaranteed states" for both parties. The electoral college would be divided by total voter percentages compared to number of available electoral votes in the state. A candidate receives an electoral vote for each time they achieve that percentage, and the final electoral would go to the candidate with the highest *remaining* popular vote after all others tallied.
Example: Ohio has 18 electoral votes and 5.3M voted. Each candidate would get an electoral vote for each 294,444 (approx. 5.55%) votes received. Final electoral vote is determined by subtracting popular vote from electorals already cast and granted to the candidate with the highest remainder