Noun
English Wikipedia has an article on:declaration of warWikipedia
declaration of war (plural declarations of war)
A formal announcement by a country or other body with military capability that it is in a state of war with another such entity.
This is a challenge to the entire trade union movement in Ireland - a declaration of war on the wages and working conditions of all workers. Joe Higgins
... the Jameson Raid was the real declaration of war. Jan Smuts
Be polite; write diplomatically; even in a declaration of war one observes the rules of politeness. Otto von Bismarck
What is not conservative about saying, 'Don't go to war unless we go to war properly with a full declaration of war and no other way?' Ron Paul
The reality is the cap-and-trade legislation offered by the Democrats amounts to an economic declaration of war on the Midwest by liberals on Capitol Hill. Mike Pence
No clap of thunder in a fair frosty day could astonish the world more than [England's] declaration of war against Holland in 1672. William Temple