As threats against the U.S. grow more complex, "demand for the unique expertise and unmatched breadth of Coast Guard has never been greater," U.S. National Security Adviser John Bolton said to the Coast Guard Academy's Class of 2019.

Bolton delivered the keynote address Wednesday to the 240 members of the graduating class, dressed in crisp white uniforms, during a ceremony on Cadet Memorial Field under a bright sun.

Highlighting some of the work the service is engaged in around the globe, Bolton said the Coast Guard is helping to enforce sanctions on North Korea, preventing piracy off the shores of Africa, and combating transnational criminal organizations throughout the Western Hemisphere.

At home, he said, the Coast Guard is responsible for protecting the U.S. maritime transportation system: 95,000 miles of shoreline; 25,000 miles of navigable channels; 1,000 harbor channels; 361 ports; 3,700 terminals; nearly 50,000 aids to navigation, and approximately 20,000 bridges.

"The safety and security of this system are essential to American trade and prosperity," Bolton said.

This is the service that the Coast Guard's newest junior officers, or ensigns, are entering. Most of the class will spend their first two years at sea on Coast Guard cutters. The four international students in the class will go back to serve in their home countries of Georgia, Honduras and Malaysia.

Superintendent James Rendon, who is retiring next week after 40 years in the Coast Guard, said the Class of 2019 is "his class" because he arrived at the academy four years ago, as they did. Having completed the 200-week program at the academy, the graduates are ready to take on the responsibilities of a commissioned officer in the Coast Guard, he said.

"For 200 weeks, we trekked and triumphed through this academy experience together," Colton Atkinson, the distinguished graduate, said in his remarks.

Atkinson said the weight of his new rank, ensign, will likely not hit him until just before he reports for duty in 30 days. Then, he and his peers will join the wardrooms at over 90 different cutters and units, where people might not be treated properly or are acting immorally, and it will be their responsibility to respond.

"It will be up to us to decide if we will create change in the organization or take the easy way out and turn a blind eye," he said.

The Coast Guard commandant, Adm. Karl Schultz, put it this way: "You will shoulder great responsibility — defending our national security, protecting our sovereignty, safeguarding our prosperity that is dependent on secure ports and waterways, and leading our dedicated Coast Guard men and women into harm's way."

The Class of 2019 is made up of 35 percent women, and 32 percent underrepresented minorities. This year, the largest number of Asian Americans — 34 — graduated from the academy in the institution's 143-year history.

One of them is Jian Zhang of New London. He said he decided to apply to the academy after meeting some cadets while in high school, and due to his dad's encouragement. After doing some research, he realized it'd be a "great opportunity for character development and to do something bigger than myself."

Of the graduates, 10 percent had an immediate family member in the Coast Guard.

Bolton shared his own tie to the Coast Guard. His father, Jack, joined the service after the attack on Pearl Harbor. He was among the roughly 5,000 Coast Guardsmen who deployed to Normandy on D-Day, June 6, 1944, and "helped save our civilization from tyranny and totalitarianism."

"All of you graduates will be worthy heirs to this noble legacy. It is a legacy that does not come to you from a prestigious family lineage with the advantages of birth and status. This is an inheritance that each one of you has earned through your sweat, through your sacrifice, through your setbacks and through your triumphs," he said.

Bolton's visit drew criticism from outside the academy, where a small group of demonstrators gathered. A day before, a group of activists had held a rally in New London to "shed light on Bolton's nefarious legacy and dangerous policy stances."

But inside, it was the usual revelry culminating four years of military and academic rigor.

Billy Bragaw and Quinton Parsons, both of East Lyme, who've been friends since the first grade and grew up watching soccer games (Parsons' dad is head coach of the men's soccer team) at the academy, and attending other events on base, were celebrating becoming ensigns together.

"He's just been my best friend throughout the entire thing. I couldn't have asked to come with a better person," Parsons said. "We made the most out of it."

Despite her new ensign shoulder boards, Camisha Moore of New London said the fact that she was now an officer in the Coast Guard hadn't hit her yet. Instead, she was reflecting on what she learned about herself the past four years.

"You have to allow yourself to fail, so you can grow from it," she said. "I learned to put all my energy and heart into everything, and if I mess up, it's OK, just bounce back and make sure that I don't make the same mistake again."

j.bergman@theday.com