The Iranian attacks on commercial vessels have led to the resumption of hostilities with the United States and a surge in oil prices.
Graham was known to have a close relationship with his sister, who has been appointed to finish out the remaining months of his term.
An officer was fielding a question from the man about directions to the Supreme Court when he noticed the gun.
The suspect was turned over to local authorities. Federal officials credited a national hub that allows law enforcement access to multiple databases.

Over the past decade the share of people with this income level living in Florida and Texas surpassed New York.
The president announced the surprise address in a Truth Social post on July 13.
Educational institutions that do not comply with legal mandates protecting students from sexual misconduct stand to lose federal funding.
Palo Alto Networks CEO Nikesh Arora said AI token efficiency needs to improve by five to eight times in the next 12 months, and 10 times the year after.
Trump called on Henry McMaster to pick Graham’s sister, Darline Graham Nordone, to serve in the interim.

The U.S. Central Command hit Iran’s main naval base with three one-way attack sea vessels on July 12.
Cases are rising quickly in Michigan, and also being recorded in dozens of other states.
Congo has been struggling with an outbreak of Ebola for months.
Tributes poured in for the South Carolina senator after his sudden death on July 11.
Nearly 74 percent of auto loan applications were approved in June.
Chief Judge Boasberg denied a temporary restraining order, allowing the Federal Trade Commission’s deceptive practices case to proceed.
The Department of Homeland Security stated that each state must take a series of five ‘common-sense steps’ to protect the integrity of U.S. elections.
The U.S. president said Friday that he has been the top target of Iran for a long time.
Overall business bankruptcy filings are also up from 2025.
A new proposed rule would cut Medicare reimbursement by 40 percent on prescription drugs for providers who already get large discounts.
The president departed from the NATO summit aboard the old Air Force One Wednesday instead of the new Air Force One donated by the Qatari government.
The proposed Memorial Circle monument would include a mezzanine at 166 feet, a 24-foot-high observation deck, and a 60-foot statue of Lady Liberty at the top.