Ryan Wesley Routh's affinity for the Ukrainian cause in the country's fight against a Russian invasion shows he knows enough about right and wrong to make an insanity defense a tough sell in connection with his alleged failed assassination plot against former President Trump, according to a Florida prosecutor.

State Attorney Dave Aronberg, who is not handling Routh's case after federal prosecutors claimed jurisdiction, said that although the suspect was seen smiling and laughing with defense lawyers in his first court appearance Monday, his "manic" demeanor doesn't strike him as criminally insane.

"He fled after all, tried to get away and escape," he said. "So that shows you that he knew the difference between right and wrong. What's ironic about this guy is that he also understood that the Ukrainians were the good guys in their fight against the Russians – but to try to make his point, he was trying to do an evil act in attempting apparently to kill someone."

TRUMP ASSASSINATION ATTEMPT SUSPECT LAUGHS, SMILES DURING FIRST COURT APPEARANCE IN FLORIDA

Ryan W. Routh, suspected of attempting to assassinate former President Trump at his West Palm Beach golf course, stands handcuffed after his arrest near Palm City, Florida, Sept. 15, 2024. (Martin County Sheriffs Office/Handout via Reuters)

An unnamed U.S. Secret Service agent saw a rifle barrel poking through the fence Sunday afternoon, nearly 12 hours after federal investigators say Routh's phone began pinging on the edge of the Trump International Golf Club in West Palm Beach.

He fled into a Nissan SUV and sped off – heading north on Interstate 95 toward his home in North Carolina.

WATCH: Florida prosecutor pokes hole in potential defense for Trump assassination attempt suspect

Police were able to quickly obtain descriptions of both the suspect and his vehicle with the help of an eyewitness, authorities said.

At the scene, investigators recovered an SKS rifle, a digital video camera and two bags – one of which had food inside, according to a probable cause affidavit filed in federal court.

WITNESS SAW TRUMP ASSASSINATION SUSPECT FLEE BUSHES, TOOK PHOTO OF GETAWAY CAR

"This is something where this guy has got a real disconnect in his value system," Aronberg said. "There's a screw loose somewhere, it's just [that] in my mind, not enough to sustain an insanity defense under the law."

WATCH: Failed Trump assassination suspect Ryan Routh captured on bodycam video

Routh had something to say about the Ukrainian conflict in a 2022 interview with Newsweek Romania.

"A lot of the other conflicts are gray, but this conflict is definitely black and white," he told the outlet. "This is about good versus evil. This is a storybook, you know, any movie we've ever watched, this is definitely evil against good."

Routh is facing federal firearm charges for allegedly possessing an SKS rifle despite multiple prior felony convictions and for the weapon's allegedly defaced serial number.

FBI Miami Special Agent in Charge Jeffrey Veltri also said that in 2019, a tipster reported that Routh might be a felon unlawfully in possession of a firearm in Hawaii. The complainant was interviewed. However, they did not verify the information. Routh was not interviewed by the FBI, which forwarded details to Honolulu authorities.

DEM REP DEMANDS SECRET SERVICE EXPAND TRUMP PROTECTIVE PERIMETER: 'UNACCEPTABLE'

Trump assassination attempt suspect Ryan Routh was seen being taken into custody Sunday, Sept. 15, 2024, in bodycam footage released Monday. (Martin County Sheriff's Office )

He's due back in court later this month, and authorities say additional charges could be forthcoming.

They could include aggravated assault for allegedly pointing the rifle at a Secret Service agent and making threats against a former president, Aronberg told Fox News Digital.

A federal attempted murder case is rare, he added.

"They may not have all the evidence yet," he said. "They're still investigating. But also, that's more of a charge at the state level than at the federal level."

President Trump plays golf at the Trump International Golf Club in West Palm Beach, Florida, Dec. 28, 2020. (Reuters/Marco Bello)

CLICK HERE TO GET THE FOX NEWS APP

Trump is scheduled to hold his first rally following the second attempt on his life on Wednesday. He will speak with voters at the Nassau Veterans Memorial Coliseum in Uniondale, New York.

Patrick Ryder, the county police commissioner, vowed attendees would "be in the safest place in the country."

Former President Trump was injured during an assassination attempt at a rally in Butler, Pennsylvania, on July 13, 2024. (AP Photo/Evan Vucci)

Trump survived another assassination attempt on July 13, when 20-year-old gunman Thomas Matthew Crooks opened fire at a rally in Butler, Pennsylvania. He struck the former president in the ear, killed a 50-year-old father of two named Corey Comperatore and seriously wounded David Dutch, 57, and James Copenhaver, 74.

Counter-snipers returned fire and killed him, but the security lapse that allowed him to climb onto a rooftop with a clear line of sight to the former president prompted multiple investigations and a shakeup at the top ranks of the Secret Service.