Democratic presidential candidate Sen. Bernie Sanders of Vermont recently said his party’s presidential primary process “distorts reality.” Specifically, Sanders criticized the timing of the Democrats’ primary schedule, which front-loads a considerable number of Southern state primary contests. In Sanders’s view, this schedule’s problem lies in the fact that states unlikely to vote Democratic in the general election have provided a series of early successes for his rival Hillary Clinton.

Sanders’s criticism raises a question: If a political party is not really competitive in a state, why would that party give that state a role in selecting its presidential nominee? A little history tells us why.

Sanders is not the first politician to complain about the influence of “non-competitive states” in the presidential-nomination process. In the late 19th and early 20th centuries, when the Republican Party was almost entirely shut out of the then-Democratic “Solid South,” leaders from the Northeast frequently complained about Southern representation at the GOP national conventions.

For example, in 1899, a Republican National Committee member from Wisconsin, Henry Clay Payne, questioned why “the states of Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, South Carolina, casting 200,076 Republican votes at the last Presidential election, should have 124 delegates in the National Convention, while New Jersey, casting 221,367 Republican votes, should have but twenty delegates?”

One explanation is simply that this is how parties have always managed their conventions. Since 1848, the Democrats have provided each state with delegates to their national conventions. The Republican Party — founded as the anti-slavery party — was a little slower to catch on. In the GOP conventions of 1856 and 1860, delegates from Southern states were not represented. But after the Civil War, the Republicans also incorporated these states. ...