Sgt. Rafael Peralta died in Iraq in 2004 after covering a grenade to save comrades. But today his family and Marine brothers wonder why a grateful nation isn't grateful enough to bestow upon him its highest military honor.

The Pentagon is awarding Sergeant Peralta the Navy Cross, the second-highest award for valor, and not the Medal of Honor, the award for which he was recommended by his fellow Marines, the Navy, and the Marine Corps.

But now the world of battlefield ethos is mixing with Beltway politics as the Peralta family, his Marine brethren, and even members of Congress protest the decision made last week by Defense Secretary Robert Gates to downgrade the award.

"I am living proof of what Sergeant Peralta did that day," says Robert Reynolds, who was beside Peralta the day he died. Mr. Reynolds says he was able to survive an explosion inside a house in Fallujah in November 2004 when

Peralta, already severely injured, snagged a live grenade and thrust it against himself, shielding Reynolds and at least three others from probable death.

Reynolds believes his friend deserves the Medal of Honor. A bipartisan group of six members of Congress agrees, and sent President Bush a letter last week expressing their "extreme disappointment" at the decision to downgrade the award to a Navy Cross and requesting a review of the Peralta case.

Pentagon officials have yet to respond to the inquiry but believe their decision was the right one, and they don't believe a new review is warranted.

The Medal of Honor is a presidential award that was chartered by Congress. Only the president can make the award unless Congress makes a special move to award it on its own.

No one thought it would come to this. The firefight in which Peralta and the other marines found themselves that day came as many experts and military officials began to recognize the extreme dangers of the insurgency in Iraq.

But few war heroes had emerged from the war, and it was thought that an act such as Peralta's would easily put him in the exclusive circle of five war heroes receiving the Medal of Honor since the war on terrorism began in 2001.

"As he lay injured, rather than using his strength in an attempt to save himself, he knowingly and selflessly opted to give his life for his fellow Marines," wrote the senior Marine commander at the time, Richard Natonski, then the two-star general making the formal recommendation.

But there was more to Peralta's act of heroism. The investigation into the firefight that day found that the marine had already been mortally wounded during the intense battle inside the insurgent house in Fallujah. What's more, it was determined that he had been felled by friendly fire.

The initial investigation acknowledged, however, that Peralta had nonetheless grabbed the live grenade when it rolled next to him and held it close to his chest before it exploded, killing him but shielding the other marines in the room from the blast.

Cpl. Jason Dunham, another marine, received the Medal of Honor posthumously last year after he placed his helmet over a live grenade to shield marines nearby in another firefight in 2004.

But Mr. Gates had lingering concerns, and he asked five individuals, including a neurosurgeon and two forensic pathologists, to review the Peralta case.

Using additional forensic information not available during the initial investigation, according to a defense official, each of the five individually concluded that Peralta's act, while heroic, did not merit a Medal of Honor. The findings focused on doubt as to whether Peralta could have performed this deliberate act after being mortally wounded. Gates agreed that that left enough doubt.

"Secretary Gates did not arrive at this decision lightly, which is evident by the rigorous and thorough review that was conducted," says Bryan Whitman, a Pentagon spokesman. "This decision in no way detracts from Sergeant. Peralta's courageous and selfless sacrifice."

The review that led to Gates's decision points up how the awards process has changed significantly over the years. Whereas at one time eyewitness accounts almost always sufficed, now technology has crept in.

In this particular action, there was some contradictory evidence that warranted further review, according to Mr. Whitman, because the standard for the Medal of Honor is extremely high and by instruction "there must be no margin of doubt or possibility of error in awarding this honor."

But the Peralta family say that if he was not awarded the Medal of Honor because there was doubt about whether his act was truly deliberate, then there is a contradiction in the citation for the Navy Cross award, which appears to note Peralta's deliberate act: "Without hesitation and with complete disregard for his own personal safety, Sergeant Peralta reached out and pulled the grenade to his body, absorbing the brunt of the blast and shielding fellow Marines only feet away," reads the citation in part.

Peralta's mother, Rosa, has said she will not accept the Navy Cross award out of protest, saying it is a slight against her son, who was born in Mexico in 1979 and enlisted in the Marine Corps the same day he received his green card.

But she may reconsider and accept the award after all in coming weeks, says a family spokesman, George Sabga. If nothing is done now, new evidence could be presented later to upgrade the award. In other cases, the nation's highest military award has been made years later.

For now, the news has not gone over well across the Marine Corps, a service known for its tradition and history and where Peralta's act had already become a legend.

Former marine Reynolds, meanwhile, says that when Peralta saved his life, it gave him a new perspective, a sense of purpose as he raises his young children. "I have a second chance," he says.