Will convention boost GOP in Ohio? Why Trump shouldn't bank on it.

Swing-state convention sites provide a negligible advantage for parties, data show. Perhaps a case can be made for a more permanent, professional location.

Republicans will hold their national convention in Cleveland this week. Will its location help the GOP win Ohio, a crucial Rust Belt swing state?

That’s part of the quadrennial political calculus for both parties, after all. When Republican and Democratic leaders pick convention sites, electoral concerns play a big role.

This year’s conventions are in Ohio and Pennsylvania. In 2012, they were in Florida (Republican) and North Carolina (Democrat). In 2008, they were in Minnesota (R) and Colorado (D).

Those are all swing states, though some more so than others. In the 2012 election, each was decided by eight percentage points or less. As for this year’s convention states, President Obama carried Ohio over Mitt Romney by three points. He won Pennsylvania by about two.

The theory regarding conventions is that they’ll generate extra local press coverage and goodwill. Dollars will flow to local businesses. These dynamics will then produce a bit of a partisan edge in places where marginal gains can make all the difference in the world.

That’s the theory anyway. The bad news is that under scrutiny it probably doesn’t hold up.

Looking at state-by-state presidential election results back to 1980, it appears that convention states produced a bit of a bump over previous results for convention nominees, according to data crunched by University of Denver political scientist Seth Masket. But the bump is less than one percentage point and within the margin of error. That means it’s likely not significant.

“If convention location yielded benefits for its guest party, we would expect to see positive numbers for both parties across most years; regardless of how they did nationally, the parties should do a bit better in the states that hosted their conventions. But that’s not what we see,” writes Mr. Masket in Pacific Standard Magazine.

Other political scientists who have looked at this question have come to roughly similar conclusions.

Given that, why hold conventions in swing states? Why should the parties even bother to scatter conventions in different locations across the country every four years? It’s true the cities in question welcome the conventions with open arms, seeing dollar signs in the air. But in the end they often struggle with security costs and downtown disruption. Some attendees end up in hotel rooms that are hours away.

Maybe the US should establish a single convention location. It might be a big city with lots of hotels and convention experience (Viva Las Vegas!). It could be a secure site at a military base or some other government installation where protection against protesters or terrorism wouldn’t be a problem (finally, an unclassified use for Area 51).

Our idea: a theme park. Build it near Orlando to make use of the existing travel infrastructure. It could host tourists in between conventions to teach civics via rides that mimic a bill’s passage through Congress, say, or animatronic recreations of the Constitutional Convention.

Boring? Maybe – but trust us, parents with kids will drag them anywhere there’s a snack bar and a modicum of entertainment. So it wouldn’t be the Wizarding World of Harry Potter. The Washington World of Harry Truman might do OK nonetheless.