El Salvador's surprise military push into Haiti has stunned the gangs that run most of the capital, but the early wins may not hold once the small invading force has to actually occupy territory long-term.

• El Salvador sent 2,500 troops into Haiti and has crushed gang strongholds, killed a top gang leader, and retaken a major stadium, all without losing a single soldier so far.
• The real goal was rescuing four kidnapped Salvadoran airmen, but the mission has quietly grown into a much bigger fight against Haiti's gangs, raising the risk of "mission creep."
• The gangs are far tougher than the street gangs El Salvador's leader Bukele crushed at home — they're heavily armed, control most of the capital, and fight on their own turf, so this is a much harder fight than his domestic crackdown.
• El Salvador's military is small, so holding captured ground long-term will be tough once gangs start hitting back with snipers, bombs, and ambushes, the same pattern that trapped the US in Iraq and Afghanistan.
• The US is split on the operation — Trump backs Bukele, while the State Department is warning that Salvadoran forces are acting recklessly and risking American and allied troops.

Outlook: Bukele is likely to keep up the pressure for now, but without more foreign troops to help hold territory, El Salvador's small force probably isn't enough to permanently break the gangs' grip on Haiti.