Americans vacationing in Mexico got a rude awakening over the weekend, when the killing of a notorious drug boss prompted mass retaliatory violence by cartels across the country, including in tourist areas like Puerto Vallarta. The U.S. State Department issued a shelter-in-place order for Americans in Mexico, while Texas Gov. Greg Abbott has increased DPS operations in border regions as a precaution to keep violence from spilling into Texas.

The situation is not only impacting Americans already in Mexico, but those planning to travel there during the upcoming spring break and summer periods. Experts are warning that crackdown operations like the one that took down the man known as “El Mencho” last weekend could become more common moving forward, signaling a new era in the battle against the cartels. “The Trump administration is working and pressuring the Mexican government to do things they’ve never done before, and that is to push back against the cartels in meaningful ways,” says Jeff Addicott, Director of the Warrior Defense Project at St. Mary’s Law School in San Antonio.

Indeed, the White House confirms last weekend’s operation was carried out by Mexico with backing and support from the U.S. This marks a change in policy from Mexico, which has largely looked the other way while the cartels operated freely for years within its borders. “President Trump is a problem solver,” says Addicott. “He is not looking at this as business-as-usual, he’s pushing back…and yes, it’s because of the United States, and our CIA is in Mexico cooperating with the Mexican government, no doubt about it.”

What that means for Americans is there could be more violence and chaos south of the border in the months ahead as the U.S. and Mexico continue operations against the cartels. “This is a war zone,” says Addicott. “These cartels are virtual states, with their own military structure and finance structure.”

“This is a very dire situation, and people have refused to do anything about it,” he continues. “We’ve just been kind of whistling pass the graveyard, kicking the can down the road, the Biden and Obama administrations did nothing…now (President Trump) has recognized the problem, and the best interest of the United States is to deal with it.”