Several presidential candidates have suggested that the US military should attack Mexican drug gangs. Here’s Reuters:

Sending troops or firing missiles into Mexico to battle cartels, as proposed by Republican 2024 presidential candidates including former President Donald Trump, could lead to casualties and bloody reprisals on American soil without stemming the flow of illegal drugs, current and former U.S. military and government officials told Reuters.

This would not be the first time the US has attacked Mexico.  The justification seems to be that illegal drugs imported from Mexico kill lots of Americans.  But it’s also true that illegal guns imported from the US kill lots of Latin Americans.  Here’s The Economist, discussing the rise in violent crime in the Caribbean:

Officials attribute the escalating violence to the increased availability of firearms. The share of murders and other crimes that involve a gun has surged. . . .

Almost all the weapons are illegally trafficked. The Caribbean countries do not manufacture guns, and their governments strictly regulate them . . .

The majority of guns appear to come from the United States, and Florida in particular (see chart 2). Anthony Salisbury, head of US Homeland Security Investigations in Miami, says in the past year his agency has witnessed a “massive uptick” in weapons being smuggled from the United States to the region, especially to Haiti. Seizures are of increasingly lethal weapons, including belt-fed machine-guns and armour-piercing rifles.

Another article in The Economist suggests that Mexico is also a victim of US gun smugglers:

Few Countries are as affected by arms-trafficking as Mexico. Its 3,200km (2,000-mile) border with the United States makes it easy to smuggle firearms into the country. Criminal groups wield these weapons to devastating effect. Over 30,000 Mexicans have been murdered each year since 2017, resulting in a homicide rate of around 25 per 100,000 people. In a novel approach, the Mexican government has taken legal action against the gun industry in the United States.

In 2021 and 2022 Mexico’s government launched two cases north of the border: the first in Boston against a handful of gun manufacturers, the second in Arizona targeting gun-dealers in Tucson. The government alleges that people in the gun industry negligently, recklessly and sometimes unlawfully sell guns in full awareness that they are likely to end up in the hands of criminal organisations. 

It might seem odd to blame law-abiding US firms for the misuse of their products in some sort of downstream activity.  But doesn’t the US government blame Chinese chemical makers when their products are used in Mexican labs to make fentanyl?

Illegally smuggled drugs kill thousands of Americans.  Illegally smuggled guns kill thousands of Latin Americans.  You can argue that both guns and drugs should be legal (my view.)  You can argue that both guns and drugs should be illegal.  What I find hard to understand is how someone could view a US invasion of Mexico as a good idea while at the same time opposing a Mexican invasion of the US.