The phrase "assuming authority" is correct and usable in written English.
It can be used when discussing the act of taking control or responsibility in a situation or context.
Example: "The manager was assuming authority over the project, ensuring that all team members were aligned with the new objectives."
Alternatives: "taking charge" or "exercising control".
Recent scholarship on women in South Carolina has identified instances in which "female planters" wielded control over land and slaves, temporarily assuming authority otherwise reserved for men.
Although the bill of complaint states that respondents California officials 'have determined' that decedent was domiciled in California, it is not contended that they have or are assuming authority to assess the tax, independently of the judgment of a court.
The central bank will begin assuming authority over banks, he said, and governments will carry out changes intended to improve their ability to respond to crises and police one another's spending.
"Prince Derendil" talks in a high and refined manner and behaves like a real noble, assuming authority in all situations and regarding others as lower class (though politely so).
While the press caricatured Jackson as "King Andrew, Clayy accused the President of assuming "authority and power not conferred by the Constitution," and moved to censure the President in the Senate--the only such censure in American history.
Forest Service Chief Dale Bosworth is assuming authority over road building and logging in a third of national forests while the Bush administration revises a Clinton-era ban on those activities.
With anyone who assumes authority over you".
With her firm opinions and her ramrod posture, Apollonia assumes authority easily.
After the plane crashes, there are no adult survivors to assume authority.
Radek's Washington office assumed authority and allowed witnesses to skip the country.
When something menacing appears, our higher reasoning centers are inhibited and our reptilian brains assume authority.
