Say what you want about President Trump’s Twitter habits, he has a way of suddenly bringing an issue to the surface that people have long known about, but never wanted to confront. The only problem with his latest tweetstorm about Baltimore is that he hasn’t gone far enough.

On Friday, Trump attacked Democratic Rep. Elijah Cummings, who had been complaining about conditions at the border, by saying “his Baltimore district is FAR WORSE and more dangerous.” Trump called it “a disgusting, rat and rodent infested mess.”

He’s right about the rats. Last year, the pest-control service Orkin rated Baltimore as one of the “rattiest cities,“ behind Chicago, Los Angeles, New York, Washington, D.C., San Francisco, Detroit, Philadelphia, and Cleveland.

Naturally, Trump’s tweets are being labeled as racist. Never mind that Democratic Sen. Bernie Sanders was saying far worse things about the city a few years ago, when he said that when you go to west Baltimore you “would think you were in a Third World country.”

Trump, meanwhile, extended his attack to House Speaker Nancy Pelosi’s home town of San Francisco.

He should widen his lens even further.

Take a look at the eight other cities that beat Baltimore on Orkin’s rattiest cities list. What do they all have in common? We’ll, let’s see:

Chicago hasn’t had a Republican mayor since 1931. Philadelphia last saw a Republican mayor in 1952, Detroit in 1962. San Francisco has been Democrat-controlled since 1964. Washington, D.C., has never had a Republican mayor.

In Los Angeles, Democrats have run the city in all but eight of the past 58 years, in New York, it’s eight in the past 74 (not counting John Lindsay, who switched parties while in office). Cleveland’s been run by Democrats in all but 16 of the past 78 years.

Indeed, if you want to see what liberal Democratic policies tend to produce, go to any one of those cities, or other Democratic strongholds. Democrats promise to help the poor and downtrodden, grow the middle class, make life more fair. But their policies consistently produce the opposite.

These cities are rife with crime. Baltimore ranks No. 1 for robberies and No. 2 for murders. Many of the other rat-infested cities also rank high for violent crimes. Their infrastructure is crumbling. The middle class has largely abandoned them.

And far from tackling inequality, Democrats have made it worse. Washington, San Francisco and New York are all in the top 10 for biggest income inequality levels, according to the Brookings Institution. Other Democrat cities — Providence, Miami, Boston, New Orleans — are also on the list.

Washington, San Francisco, New York, Detroit, and Cleveland are also among the 10 worst-run cities, according to WalletHub. Three other Democratic strongholds — Oakland, Flint, Hartford — make WalletHub’s worst-run list.

Yet, whenever the desperate conditions of these cities get discussed, they’re treated either as if these problems simply fell out of the sky, that somehow Republicans are to blame, or that more taxpayer money will solve everything. The connection to liberal policies never gets made.

So, rather than focus on Baltimore and Cummings, Trump would do well to point out that it’s decades of Democratic rule that have destroyed some of the country’s finest cities. High taxes and intrusive regulations make them inhospitable to business. Government control and union cronyism encourage waste and corruption. Soft-on-crime attitudes lead to more crime, drug abuse, and rampant homelessness.

You see the same thing at the state level. Of the 10 worst-run states in the country, all but one is solidly Democratic. And of the best-run states, only one is Democratic, according to a ranking by the Mercatus Center.

This has nothing to do with race. It has everything to do with the sorts of policies the left has implemented, policies that history shows over and over again do not work.

This is the message the public needs to hear. And it’s one Trump is uniquely qualified to get across.

— Written by John Merline