In the spring of 2017, a Republican congressional staff member submitted an application to carry a handgun in Maryland, one of fewer than 10 states requiring citizens to prove they have a good reason to carry firearms.

Maryland, which has some of the country's strictest gun laws, received more than 600 appeals of permit denials in 2018. Edward Holmes Whalen, then a staffer on the Senate's Indian Affairs Committee, had presented a rather novel justification in his application - working with the Trump administration, he said, posed great danger.

"I believe either me or my family, while traversing the State of Maryland," Whalen wrote, "are at a greater risk to be exposed to hostile encounters with individuals who vehemently (and violently) oppose the President's vision for our country, particularly as it relates to foreign policy and terrorism."

Whalen's application was denied. He appealed and lost. And now his case is in front of the Maryland Court of Special Appeals with backing from Maryland Shall Issue, a gun rights organization pursuing legal and legislative paths "to promote and defend the right of armed defense that belongs to every responsible, law-abiding Marylander."

Whalen's challenge against Maryland is one of dozens, perhaps even hundreds, of test cases that gun rights advocates have brought in state and federal courts around the country following the Supreme Court's landmark 2008 decision in District of Columbia v. Heller. In that 5-to-4 decision, the justices ruled that the Second Amendment guaranteed individuals the right to own guns regardless of military service.

But states and federal courts have yet to definitively sort out a crucial question raised by Whalen and others - whether the constitutional right extends beyond a gun owner's home. The U.S. Court of Appeals for the 4th Circuit has previously ruled in Maryland's favor, holding that "as we move outside the home, firearm rights have always been more limited, because public safety interests often outweigh individual interests in self-defense."

Legal experts say the issue is barreling toward the Supreme Court.

All of the post-Heller litigation revolves around a set of important questions: "Where can you take guns? What kind of guns are protected?" said Darrell A.H. Miller, co-director of Duke University's Center for Firearms Law.

In Maryland, citizens who want to carry a gun outside the home must file an application with the State Police. Applicants are required to pass a criminal-background check and a handgun training course. Most critically, they must prove a "good and substantial reason" to carry a gun "such as finding that the permit is necessary as a reasonable precaution against danger."

Whalen, who declined to comment for this article, lives in Washington, though he can "literally throw a baseball" from his home into Maryland, according to his testimony during his appeal. To drive into Maryland with a handgun, Whalen would need a permit, which he applied for in March 2017. His application was denied that July.

Whalen, then 34, set off on an odyssey of reviews and appeals, first on his own and then with legal representation provided by Maryland Shall Issue. In letters of appeal and testimony before a state review board, Whalen offered several justifications for his application.

One of them was his father, Laurence J. Whalen, a federal tax judge.

"Individuals may seek retribution for opinions or rulings that were not in their favor," Whalen wrote, arguing he needed a firearm to defend "myself, and my family, were such an incident to occur while in my father's company."

Another reason: Whalen had been the victim of identity fraud in 2007 by a man in California. Whalen pursued the suspect "vigorously," therefore necessitating his need to arm himself, he said.

In addition, Whalen served as an Advisory Neighborhood Commissioner in Ward 3. "I regularly encounter constituents with strong feelings about my decisions," Whalen wrote.

But it was Whalen's Trump argument that caught the attention of legal experts.

"It is no secret that the political and social climate in the D.C. Metropolitan Area has become divisive and, at times, violent," Whalen wrote. "The threat of violence that is assumed by members of Congress, and their Staff, is very real."

In a separate letter, Whalen referenced the 2017 attack on several members of the Republican congressional baseball team while they practiced in Alexandria, Virginia. "This kind of attack is especially disturbing in the context of threats I have received in the past as a personal office staffer," Whalen wrote.

Maryland's Handgun Permit Review Board, which reviews appeals of denials by the State Police, agreed with an initial finding that Whalen offered no evidence of threats. The board itself is under some dispute, with Republican Gov. Larry Hogan recently vetoing legislation to dissolve the entity - made up of political appointees - in favor of administrative judges.

As for Whalen's political climate justification, Miller, the co-director of Duke's gun law center, said: "I really don't know what to make of it. I haven't seen an argument that says the political climate is really decaying and therefore I need a firearm because of the political climate. I just have never heard of anything like that before."

But now that the case has reached the Maryland Court of Special Appeals, Whalen's threat justifications don't really matter.

In legalese, Maryland is a "may issue" state. The state may issue a license if it finds there is a "good and substantial reason."

Whalen and gun rights organizations want Maryland to become a "shall issue" state, meaning that if an applicant passes objective hurdles such as a criminal-background check and training course, they should be issued a license to carry.

Whalen has already passed those hurdles.

"Exercising a right does not depend on whether or not you have a special need, or a "good and substantial reason," in the state's parlance," said Mark W. Pennak, the president of Maryland Shall Issue. "Your right to report in the newspaper does not depend on whether or not you have a special need to report."

The Constitution, Pennak added, provides that right "to the people, and not a subclass of the people."

In Whalen's appeal in Maryland, his lawyers argued the court "should thus strike down the good and substantial reason requirement and order the issuance of the permit."

Even John Adams - or the ghost of John Adams - gets the point, they wrote.

“In defending the British soldiers charged in the Boston Massacre, John Adams conceded that, in this country, ‘every private person is authorized to arm himself; and on the strength of this authority I do not deny the inhabitants had a right to arm themselves at that time for their defense.’”