The phrase "argued staunchly" is correct and usable in written English.
It can be used when describing someone who is firmly and passionately expressing their viewpoint or position on a particular issue.
Example: "During the debate, she argued staunchly in favor of environmental protection policies."
Alternatives: "defended vigorously" or "contended strongly".
Since that account formed the backbone of the case against Syed, fans of Serial argue staunchly for his innocence to this day.
Observatorio Eclesial argues John Paul staunchly backed Degollado despite accusations that the priest raped young boys from the 1950s to the 1990s.
An 1871 Times editorial that staunchly argued against statehood said the territory was "the heart of our worst civilization" — a theme that Walter White would later fully embody.
When Trump made a sly reference to what "the second amendment people" might be able to do to stop Clinton's agenda if she got to appoint supreme court justices, a remark widely interpreted as a reference to insurrection or assassination, the NRA staunchly argued that Trump had only been talking about gun rights advocates turning out to the polls to defeat Clinton.
I thought wistfully of the many times I had argued with state education bureaucrats who staunchly opposed the idea of actually naming a good book that students ought to read in any particular grade.
In 2004 the Democrats argued, with some evidence, that Ken Blackwell, the staunchly conservative secretary of state, was not overzealous in ensuring that all Democrats could exercise their right to vote.But the polls are nevertheless surprisingly close.
Postal unions have staunchly opposed such moves and argued that they will lead to the so-called death spiral, in which reduced services inevitably lead to the agency's demise.
In 1994, Bush was staunchly opposed to gay rights, and argued that gay men and lesbians did not deserve special legal protection, and that "sodomy" should not be "elevated to the same constitutional status as race and religion".
As the staunchly right-wing Web site The American Dream argued, Supporters of Texas Governor Rick Perry are not going to like this article at all.
Two council members staunchly opposed to the plan, Corky Booze and Nat Bates, argued it wasn't worth it.
