“Do something,” the crowd chanted at Ohio Gov. Mike DeWine after the recent mass murder in Dayton.

Thoughts and prayers have their place, but they are no substitute for action.

The sheer number of mass shootings in America is an epidemic: there have been at least 254 so far this year, according to a list compiled by the nonprofit Gun Violence Archive. A mass shooting is defined as any incident in which at least four people were shot (excluding the shooter).

The American people must demand that our elected officials take reasonable, common-sense steps to put limits on the sale of military-style weapons to mass murderers.

A majority of Americans support reasonable limits, according to many polls. For instance, 69 percent of Americans support moderate or strict regulations on guns, according to a Reuters/Ipsos poll earlier this year.

Important restrictions have been passed in Florida over the past two years, including:

• A “red flag” law that takes firearms out of the hands of those suffering from mental illness.

• An increase in the age for purchasing a firearm from 18 to 21.

• A required three-day waiting period for purchasing rifles and other long guns.

And now a constitutional amendment to ban assault rifles is moving toward the 2020 ballot in Florida.

The fact is that tough restrictions on firearms — short of bans — have a long tradition in America.

In the Wild West of the 1880s, it was common for cities like Tombstone, Ariz., and Dodge City, Kan., to require visitors to disarm before entering town.

In 1934, Congress passed the National Firearms Act in response to massive gang violence marked by the use of Thompson submachine gun, better known as the “Tommy Gun.”

The act severely regulated machine guns as well as short-barreled rifles and silencers: a $200 tax at the time was equivalent to almost $4,000 in today’s dollars.

Severe restrictions short of a ban may be more palatable politically for the devices commonly used in mass shootings, such as body armor and huge magazines.

The Dayton shooter used a 100-round magazine with 250 rounds of ammunition and an AR-15 pistol that was modified to act like a rifle; he was also wearing body armor.

Despite an extraordinarily quick response by Dayton police, it wasn’t enough to stop a mass murder.

On a broader level America must be just as diligent in preventing domestic terrorism as it is in fighting Islamist terrorism.

In fact, far-right violent extremists were responsible for 73 percent of fatal violent extremist incidents since 2001, reported the Government Accountability Office.

These extremists are fueled in their hate by social media accounts that must also be monitored and stopped for figuratively “shouting fire in a crowded theater.”

Private industry must shut down accounts that are clearly fueling violence — and Americans must put pressure on these providers to ensure such action is taken.

The Bill of Rights must not be used as a shield while Americans are being killed.