Whichever ticket wins the election in November, it will be the first time in decades that the president, the vice president or both have children serving in the armed forces while the nation is at war.
Democratic vice presidential candidate Joe Biden's son Beau is a captain in the Delaware National Guard. His unit, the 261st Signal Brigade, reports for training in October, and they expect to be in Iraq within a few months.
"My dad has always been there for me, my brother and my sister, every day," Beau Biden said in his speech at the Democratic National Convention. "But because of other duties, it won't be possible for me to be here this fall to stand by him the way he stood by me."
John McCain currently has two sons in the military: midshipman John McCain IV, now in his final year at the Naval Academy, and Marine Lance Cpl. Jimmy McCain, who has already served a tour in Iraq. Track Palin, the 19-year-old son of McCain's running mate, Alaska Gov. Sarah Palin, will be deployed to Iraq after a farewell ceremony in Alaska on Thursday.
McCain doesn't talk about his son's service, but at the Republican National Convention, his wife, Cindy, spoke of her struggle as a mother watching her son go off to war.
"The stakes were never more clear to me than the morning I watched my son Jimmy strap on his weapons and board a bus headed for harm's way," she said.
Reportedly, Cindy McCain had arranged to see her son off as his plane left for the Middle East, but Jimmy told her not to come. The other Marines' mothers were not allowed to do the same, and he did not want special treatment.
The three candidates' sons have very different roles in the military. Lance Cpl. McCain was a grunt in Iraq's Anbar province. Pfc. Palin is in the 1st Stryker Brigade Combat Team of the 25th Infantry Division out of Fort Wainwright, Alaska. Capt. Biden is Delaware's attorney general, and he is expected to act as a trial counselor for his unit.
For security reasons, the military will not disclose the locations in Iraq where Palin and Biden will serve. Pentagon officials and members of their units all say that the men will be treated like any other soldier or Marine.
But retired Col. James Currie, a professor at the National Defense University, says that equal treatment could prove dangerous.
"It simply wouldn't be fair to the other members of the unit to not give them special treatment, and in fact, get them out of there," Currie says. "Can you imagine the propaganda victory if al-Qaida or some organization over there were to injure, or kill or, heaven forbid, capture the son of a president or a vice president?"
Only two American presidents have had a child fighting during wartime while they were in office. Four of Franklin Roosevelt's sons served in World War II, and Dwight Eisenhower's son John served in Korea.
"My dad and I talked about it, and I told him I would not be captured," Eisenhower says. "I would do myself in before I was captured. That was the agreement between us."
Although Eisenhower eventually retired as a one-star general in the Army, he now says his father's decision to leave him in combat was a mistake.
"The military career of a young guy is not that important," he says. "What somebody could do to the burdens the president is carrying is just too much. It would have destroyed my military career if I had not gone to Korea, but I was not that important."