The phrase "action is tantamount" is correct and usable in written English.
It can be used to indicate that one action is equivalent to or has the same effect as another action.
Example: "In this case, failing to report the incident is tantamount to condoning the behavior."
Alternatives: "action is equivalent" or "action is synonymous".
The action is tantamount to arrest.
"This action is tantamount to condoning the death penalty.
*If a health plan refuses to authorize an operation or other medical procedure, that action is tantamount to denying a claim, and the patient may appeal.
In the world of academic publishing, UC's action is tantamount to a nuclear shot.
Peter Givler, the executive director of the Association of American University Presses, said Google's action was "tantamount to saying that Google can make copies of every copyrighted work ever published, period".
"This is a sad day for America as a whole," Sheriff Arpaio said, suggesting that the federal government's action was tantamount to setting up a neon welcome sign for illegal immigrants.
When South Carolina sought to nullify a federal tariff of 1828, Jackson insisted that such unilateral action was tantamount to treason, and threatened to uphold federal supremacy by force if necessary.
In an interview explaining the step, Vladimir Shkolnik, the minister of energy and mineral resources, said the action was tantamount to "the governor of Nevada announcing that he would close Nevada's nuclear test site".
In their public comments, those on the Finalist Committee disagreed about whether this action was tantamount to censorship.
Critics say the actions are tantamount to socialism, and a year ago, Blinder admits, few would have advocated such extreme measures.
When asked whether the Myanmar government's actions were tantamount to genocide, Mr. Gates stopped short of that accusation.
