Earlier this month, President Donald Trump declared a national emergency to secure funds for a wall on the southern border. You can draw a line from that decision straight back to 225 years ago, when President George Washington set a precedent for executive authority by calling up a militia to put down the Whiskey Rebellion in Western Pennsylvania.

By 1791, America's young federal government was facing massive debt accumulated from the Revolutionary War. Looking to reduce that debt, Secretary of the Treasury Alexander Hamilton imposed an excise tax on domestically produced spirits, the most popular of which was whiskey.

The new tax didn't sit well with western Pennsylvanians, who produced and consumed a lot of whiskey, according to Denise Cummins, a curator for the David Bradford House in Washington, Pennsylvania. Bradford was the deputy attorney general for Washington County, and his home was turned into a museum for the Whiskey Rebellion.

For most individual farmers in this region, distilling whiskey was the most economical way to use their excess grain. They’d use the money generated by whiskey sales as supplementary income for their families. “So [the tax] was a real issue for them,” Cummins said. “The first few tax collectors came in and were not welcomed. They were run off. Some were tarred and feathered.”

For the next few years, a good portion of Appalachia refused to pay this tax. Heinz History Center curator Leslie Przybylek said much of this unrest stemmed from a disconnect between the young western states and the East Coast, where the federal government was established. Distillers on the East Coast were generally larger and produced more, so the regressive excise tax didn’t affect them as much.

“[Western Pennsylvania] saw that this tax is something coming from ‘those people’ in that isolated area that didn’t really relate to what was going on right around here,” Przybylek said.

President Washington met with protesters in an effort to reconcile the situation, but he wasn’t successful. After several violent episodes broke out, protesters, led by Bradford, planned a march to Pittsburgh. When President Washington heard about this, the crowd was rumored to be in the thousands, even though in reality, it was more like the hundreds. Cummins said the idea that thousands of countrymen were marching in opposition of a tax levied by the federal government prompted President Washington to use the Militia Acts of 1792.

“It authorized him, in times of insurrection or invasion, to call up the militia from the individual states and take action,” Cummins said.

This was the first major usage of presidential authority since the passage of the Constitution. Under the act, Washington federalized nearly 13,000 militiamen from New Jersey, Maryland, Virginia and Pennsylvania. The action required approval from a Supreme Court Justice, which Washington received in August of 1794. He remains the only president to personally lead troops into battle while commander-in-chief.

Most of the protesters near Pittsburgh dispersed upon hearing that the militia was headed in their direction. At that point, most of the federal militia returned home, too.

“Washington was realistic,” Przyblek said. “He knew just the threat of [the militia] coming dissuaded the worst of it.”

A contingent of the troops arrested some of the rebels and took them to Philadelphia for trial, but charges were dropped mostly due to lack of evidence. Bradford, who had fled to Louisiana during the rebel retreat, was tried in absentia for treason, and later pardoned by President John Adams.

But Washington’s decision to federalize the militia and enforce the excise tax was a first for the country. It represented the government’s ability to enforce its laws, with the president at the helm. Over the years, President Abraham Lincoln used his executive authority to blockade Confederate ports during the Civil War. President Franklin D. Roosevelt declared a national emergency during World War II. Then, in 1976, the National Emergencies Act was passed, spelling out the process. President George W. Bush issued a national emergency after the 9/11 attacks.

Duquesne University School of Law associate professor Jalila Jefferson-Bullock said in modern times, nearly every president has used the power.

“It usually happens when there is some sort of economic sanction being imposed that needs to happen right away,” Jefferson-Bullock said. “Or when there is an actual natural disaster that we could all recognize as a typical type of emergency.”

In President Trump’s case, she said, money already appropriated for military construction projects can be used for new projects, like a border wall. The House of Representatives recently introduced legislation that would block the president’s declaration. But even if it passes the Senate, Jefferson-Bullock said, the president can still veto it; and that veto can only be overridden by a supermajority vote.