An annual gala to honor the federal government’s most dedicated employees began Thursday evening with an announcement: The singer who was supposed to lead the crowd in the national anthem could no longer do so because of the government shutdown.

“So, we are going to have all of you sing with all of us,” said Max Stier, president of the Partnership for Public Service, a nonpartisan organization that hosts the annual party to recognize the achievements of government workers and hand out the Samuel J. Heyman Service to America Medals — better known as “Sammies,” which are considered the Oscars of the government world.

That was just one of the challenges of hosting the glitzy event during a government shutdown. Several finalists were not allowed to travel to Washington for the ceremony. Of this year’s nine honorees, four were deemed “nonessential” and were sent home by their agencies as President Obama and congressional Republicans try yet again to resolve their differences over the Affordable Care Act and other issues.

The shutdown dominated cocktail-hour conversations and continued into the evening. There were some jokes, like when Director of National Intelligence James R. Clapper Jr. apologized for wearing a mere suit to the black-tie event: “My tuxedo was deemed nonessential.” Clapper also said it was difficult for him not to vent about the shutdown.

This has been a difficult year for government workers. There was sequestration, plus ongoing budget cuts, pay freezes and furloughs. There were scandals in a few agencies that soured public opinion of all federal workers. Now, thousands of workers are furloughed, and their pay could take a hit.

But over a steak dinner and glasses of wine, government workers were not called nonessential, overpaid or lazy. They were called public servants and were profusely thanked for seeing the value of working for the government.

“The bottom line is: We will never get what we want from our government if we focus only on what is wrong and don’t celebrate what is right,” Stier said.

The nine Sammies winners, all nominated by their colleagues, spoke emotionally of working for the government, often using the words privilege, honor and mission. The award is named for the philanthropist who founded the Partnership for Public Service to revitalize the federal government.

“It’s a calling — not just a career, but a call to service,” said winner John MacKinnon, 52, an investigations group supervisor with Immigration and Customs Enforcement who oversaw a team in Boston that scoured images of child pornography, looking for any clues that would allow them to identify and rescue the child – and arrest the producer. So far, the team has rescued more than 160 children and arrested more than 50 suspected predators.

Other Sammies recipients include a Centers for Disease Control and Prevention medical officer who eradicated polio in India, National Institutes of Health researchers who stopped the spread of a rare, deadly strain of antibiotic-resistent bacteria through a hospital, and a State Department adviser who organized a conference for young people from Saudi Arabia, Egypt, Iran, Israel and the Palestinian territories.

Four of the winners have been deemed nonessential, including Kevin T. Geiss, the Department of the Air Force’s deputy assistant secretary for energy who found ways to save the government more than $1 billion in 2012 alone.

David Lavery, 54, is a program executive at NASA who shepherded the development and launch of the Curiosity rover that explored the geology and climate of Mars. With the shutdown, the rover is kept in a safe spot with stable power, but it is not allowed to explore. The team also had to cancel its biannual meeting. NASA is one of the hardest-hit agencies, with nearly all of its employees on furlough.

“We went there with a specific mission in mind, and we want to fulfill that mission, and we are not being allowed to do it,” Lavery said. “To not be able to do this because everyone cannot agree on the budget is incredibly frustrating.”