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

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

From BBC

Prof Kivutha Kibwana, a law scholar and a former county governor, urged dialogue in his post on X: "The most dangerous thing for a government to do is to declare war on its youth."

From BBC

The attacks prompted Mr. Netanyahu to declare war on the militant group.

From Washington Times

Those of a certain personality declare war on their own vulnerabilities, as my father did, fighting to hold onto his dignity.

From Los Angeles Times

The Arizona’s death toll accounted for nearly half the military personnel killed at Pearl Harbor on Dec. 7, 1941, which President Franklin D. Roosevelt declared “a date that shall live in infamy” and which prompted the United States to declare war on Japan.

From New York Times