On the 250th anniversary of the U.S. Army, President Trump is throwing a massive military parade on Saturday, showcasing America’s Armed Forces in a grand display of strength in the nation’s capital. 

The parade, described as a once-in-a-lifetime spectacle — which just happens to coincide with Mr. Trump’s 79th birthday and the annual Flag Day celebration — is set to feature an extraordinary display of military might, including tanks, aircraft, and more than 7,000 Army personnel. 

The parade — as with virtually all things political these days — has split the nation.

While hardcore conservatives in Congress, like Congresswoman Marjorie Taylor Greene, effusively support the display, other more moderate members aren’t as excited. 

“Never been a big fan of goose-stepping soldiers in big tanks and missiles rolling down the street,” Senator Paul, a Republican of Kentucky, said. “We were always different than the images you saw of the Soviet Union and North Korea. … I’m worried about the image that it isn’t necessarily the best image to show.”

Senator Kennedy, a Republican of Louisiana, said the parade is overkill. 

“The United States of America is the most powerful country in all of human history. We’re a lion, and a lion doesn’t have to tell you it’s a lion,” he said. “Everybody else in the jungle knows … I would save the money, but if the president wants to have a parade, he’s the president, and I’m not.”

A majority of Americans believe the parade is not a good use of government funds, according to recent polls. It is expected to cost as much as $45 million, with up to $16 million of that to be spent on repairing Washington streets after expected damage by the heavy tanks. But parade planners say they have mitigated possible road damage, which will greatly reduce the cost.

“Critics may question the high price tag, but the Army’s 250th birthday is a once-in-a-lifetime event,” a spokesman for the III Armored Corps based at Fort Cavazos, Texas, Colonel Kamil Sztalkoper, told the Associated Press, noting that the military has been planning events for more than a year.

The parade is, with little doubt, an indulgence by Mr. Trump, who reportedly was blown away when he attended France’s annual Bastille Day, which celebrates that nation’s revolutionary history, in 2017. 

“It was one of the greatest parades I’ve ever seen,” he said afterward, adding that he told President Macron he wanted to “top” it.

The Secret Service is preparing for the possibility of protests at the parade, after days of violence in Los Angeles and other cities over the Trump administration’s deportations.

“We’re paying attention to what is happening there, and we’ll be ready for that if it were to occur here,” the special agent in charge of the Secret Service’s Washington field office, Matt McCool, says.

The entire celebration is deemed a National Special Security Event because the Department of Homeland Security says it is a potential target for terrorism or other criminal activity.

Mr. McCool says nearly 20 miles of anti-scale fencing is being installed to secure the event. Fencing was already going up around the White House on Monday following the unrest in Los Angeles. There will also be 17 miles of other barriers installed. The Secret Service says drones will fly above the area as part of its layered security plan.

Meanwhile, protesters across the country also are set to take to the streets Saturday for “No Kings” rallies in more than 1,800 cities and towns to showcase resistance to Mr. Trump. Organized by a coalition of left-wing activist groups, “No Kings” day bills itself as a “mass mobilization in response to increasing authoritarian excesses and corruption from President Trump.” Organizers anticipate this will be the largest anti-Trump protest to date.

“The goal here is to deprive Trump of what he wants in this moment, which is a story about him being the all-powerful political figure of our time, and instead create a contrast with normal, everyday people demonstrating that power in this country still resides with the people,” a co-founder, Ezra Levin, of a progressive group, Indivisible, said.

Mr. Trump’s parade will showcase more than 150 military vehicles, including iconic M1 Abrams tanks, M2 Bradley and Stryker fighting vehicles, and M109 Paladin howitzers. Video footage shared on social media shows a mile-long column of tanks arriving in the capital over the weekend following a freight train journey from Texas.

Aerial demonstrations featuring 50 aircraft will be a highlight, including flyovers by World War II- and Vietnam-era planes, along with modern F-22 fighter jets. Helicopters, including CH-47 Chinooks, AH-64 Apaches, and UH-60 Black Hawks, will make up part of the day’s aviation showcase. There will also be a parachute jump by the Golden Knights demonstration team.

The parade will also feature elaborate military displays, including precision-guided missiles and the High Mobility Artillery Rocket System, which has seen use in Afghanistan, Iraq, and Syria. 

The event starts at 11 a.m. EDT with displays and live music, followed at 6:30 by the hour-long parade on a route that runs along Constitution Avenue between the Lincoln Memorial and the Washington Monument. After that, there’ll be a concert held near the Monument, with the day culminating in a fireworks display starting at 9:45 p.m. 

The skies are forecast to be cloudy in the morning, with scattered showers and thunderstorms in the afternoon. The high will be around 80 degrees with a light breeze; chance of rain is 50 percent.

Mr. Trump will watch from a review stand on the Ellipse, just south of the White House. 

“Oh, the parade is going to be incredible. It will be a parade like we haven’t had in many, many decades,” Mr. Trump said on Thursday. “And it’s a celebration of our country. It’s a celebration of the Army actually. … We have the greatest weapons in the world and the greatest people in the world. It’s gonna be a big parade.”

Ambassador Monica Crowley, chief of protocol for the United States, emphasized the significance of the event. 

“When the president came into office on Jan. 20, he made it clear that he wanted to … feature the United States Army as the first branch of the United States military to be constituted of the American republic, and he wanted to give the U.S. Army a very special birthday parade,” she told Axios.

But don’t plan on watching the events on TV: “ABC News, NBC News and CBS News are unlikely to pre-empt regular TV programming for coverage, according to people familiar with their plans,” Variety reported. Instead, the networks will use their streaming services to cover the day’s activities.