declare war on

Idioms  

1. Also, declare war against. Announce one's intent to suppress or eradicate something or someone. For example, The police have declared war on drug dealing in the neighborhood, or Several gangs have declared war against each other. This usage transfers the literal sense of the term, “to state formally one's intention to carry on hostilities against another power,” to a somewhat smaller scale.

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Example Sentences

"Today we declare war on those involved in the smuggling -- and anyone who breaches the forbidden area will be targeted," Katz said Thursday.

From Barron's

"The main enemy is outside, in the streets -- the criminal gangs, the crime groups... we must declare war on them," he said.

From Barron's

Under US law, the president does not have the sole power to formally declare war on another country.

From BBC

This week saw Roman Catholic cardinals meet to choose the next pope, people across Europe mark the 80th anniversary of the end of World War Two, and Donald Trump declare war on foreign films.

From BBC

It could even declare war on Venezuela or Tren de Aragua — that would clear things up in a hurry.

From Los Angeles Times