WASHINGTON - This week the Democratic presidential hopefuls will meet in Detroit for their second set of debates. Next summer the party will hold its nominating convention in Milwaukee. And this spring Democratic front-runner Joe Biden officially kicked off his campaign in Philadelphia.

Notice a pattern? Early indications are that the 2020 presidential campaign is going to be logging a lot of frequent flyer miles in and out of the Industrial Midwest and there’s a good reason for that. Those three states, Michigan, Pennsylvania and Wisconsin, look like they will hold the keys to the White House. All were close in 2016 and President Trump’s narrow wins there carried him over the finish line.

Together those three states hold 46 electoral votes and without them, Trump would not be in the Oval Office.

Trump captured 304 electoral votes in 2016, well over the 270 needed to win, but without these three states in the Industrial Midwest, he would have come up short.

Trump captured 304 electoral votes in 2016, well over the 270 needed to win, but without these three states in the Industrial Midwest, he would have come up short. The blow was even bigger for Democrats because their presidential candidate had won all three states in every election going back to 1992.

Trump’s campaign was impressive in the way it blew apart the “big blue wall’ the Democrats had built around the Great Lakes. But the margins in Trump wins were razor-thin, a mere 78,000 votes combined in the three states. He didn’t win any of them by even a single percentage point.

But the margins in Trump wins were razor thin, a mere 78,000 votes combined in the three states.

In Michigan, the margin was about 11,000 votes or .22 percentage points. In Pennsylvania, it was 44,000 votes and .71 points. And in Wisconsin, it was about 23,000 votes and .77 points.

Those are remarkably close votes and that’s one reason why the states are such focus for 2020. Democrats think those states can be flipped back to their side.

When you look at the 2016 vote totals in those states compared to 2012, a pattern emerges that has to make Democrats groan. In all three states, the big urban counties that produce big margins for Democrats (25 points or more), did not keep up with the voting pattern in the rest of the state.

In Michigan, Wayne County, the home of Detroit, produced 4 percent fewer votes in 2016 than it did in 2012, but the rest of the state produced 3 percent more votes.

In Michigan, Wayne County, the home of Detroit, produced 4 percent fewer votes in 2016 than it did in 2012, but the rest of the state produced 3 percent more votes. In Pennsylvania, Philadelphia produced 3 percent more votes in 2016 than it did in 2012, but the rest of the state produced 8 percent more votes. And in Wisconsin, Milwaukee produced 12 percent fewer votes in 2016 than it did in 2012, while rest of the state saw a much smaller decline, only 2 points.

Milwaukee produced 12 percent fewer votes in 2016 than it did in 2012, while rest of the state saw a much smaller decline, only 2 points.

Some Democrats look at those numbers and see the answer to their “blue wall” problem. Just drive up the vote from those counties from their voters and the states will fall into their column, particularly in Michigan and Wisconsin. The vote from Wayne dropped by 33,000 and Hillary Clinton only lost Michigan by about 11,000. In Milwaukee, the vote dropped by a massive 51,000 votes and Clinton lost the state by 23,000 votes.

Turnout equations can be complicated. Driving up the vote in just one place usually isn't easy.

Of course, that’s a somewhat simplistic answer. Turnout equations can be complicated. Driving up the vote in just one place usually isn’t easy.

And remember the Trump campaign knows these numbers as well. You can rest assured that they will be working to drive up the margins in their strongholds in those states – blue-collar suburbs and rural areas.

But all of that only proves the general point. Get used to lots of rallies with datelines like Oshkosh, Reading and Kalamazoo. There are battleground states in every election. But as of July 2019, the road to the White House goes through straight through the Industrial Midwest.