Pennsylvania is considering a change in how it allocates electoral votes in Presidential elections.  Currently, like nearly all other states, Pennsylvania’s electoral votes are up for grabs in a winner-take-all contest.  All 20 of its votes go to the candidate who receives the largest share of the popular vote in the state.  The state’s Republican party, currently in control of the legislature and the governor’s office, is considering a switch to a system in which each of the 18 congressional districts in the state would award a vote to the winner in that district.  (I believe the remaining two would be decided by state-wide popular vote.)

There are a number of ways to think about the incentives to switch between these two systems.  One way is to ask how it will effect the overall flow of campaign dollars/favors to the state.  On this score, in a state like Pennsylvania, the proportional-vote system is clearly better.

Only one Republican Presidential candidate has carried the state in the last 25 years.  The cost of increasing Republican vote share by a few percentage points would be wasted in a state where Democrats begin with such a large advantage. But in a proportional system such an investment can pay off.  The Republican party will now spend to compete for the marginal vote and Democrats will likely spend to defend it.

Of course the real question is how a state with a strong Democratic leaning could be expected to vote to switch to a system that will not only channel money to Republican districts but also help the Republican Presidential candidates.

Note that the opposite ranking holds in a more competitive state.  If the two parties are on equal terms in a state, then a winner-take-all system gives a huge reward to a party who invests enough to gain a 1% advantage in vote-share.  By contrast a proportional system offers at most a single vote in return for that same investment.  Such a state maximizes its electoral spoils by sticking with winner-take-all.  And with no majority party these economic incentives should dominate.

Taking stock of both of these two cases, it is not surprising that almost all states use a winner-take-all system.  Indeed, Nebraska, one of the few states with a proportional system may soon switch to winner-take-all.