The phrase "pledge loyalty" is correct and usable in written English.
It is commonly used to express an oath of loyalty or fidelity to a person, group, or cause. For example, "I pledge loyalty to my country and its laws."
First, every performer must pledge loyalty to New York.
Lire made no promises and refused to pledge loyalty.
Few Hong Kongers pledge loyalty to China's Communist Party, Mr. DeGolyer said.
To have any influence with George Bush, he needed to pledge loyalty.
They pledge loyalty to a political leader and then betray him.
OTHER OFFICERS MOVE UP Coolidge's Letter, Brought by Airplane, Read to Delegates, Who Pledge Loyalty.
During the GOP primaries, Trump asked attendees at his rallies to physically pledge loyalty.
Senior princes were then assembled at a Riyadh palace to pledge loyalty to the new order of succession.
"It wasn't required to pledge loyalty and renounce the U.S.," Mr. May told The Blaze on Monday.
"Those groups that support and pledge loyalty to Mr Xi appear untouched," the novelist wrote last month.
So far, the succession process has gone smoothly: many of those who objected to Mansur's selection have agreed to pledge loyalty to the new leader.
