Reports of a covert US assassination campaign in Mexico, paired with legal pressure on politicians from the ruling party, point to a dangerous new stage in US-Mexico relations.

• Anonymous agency sources describe a covert CIA effort to kill cartel operatives inside Mexico, including a car bombing in March.
• Two CIA officers died in a car crash in Chihuahua earlier, and the official account has never fully added up.
• US indictments and visa bans have hit politicians almost only from Morena, the leftwing governing party — opposition figures with their own cartel ties are being left alone.
• Three border-state Morena governors lost their US visas and are reportedly cooperating as informants, which looks like an attempt to control the border ahead of Mexico's midterms next year.
• Taking down Sinaloa's governor backfired: rival factions of the Chapo and Mayo camps are now settling scores and violence there is worse.

Outlook: With the same administration already striking Iran, escalating in Ukraine and talking openly about bombing Mexico, groundwork is being laid for possible US military action across the border.