Feb. 28, 2008 -- Last May, Sen. Barack Obama, D-Ill., was issued a full-time Secret Service detail, an unusual event so early in the election season, but one that reflected the potential threat against him.
Yet, despite the intense security ring protecting the presidential candiate, questions remain about security, especially among the huge crowds the candidate draws.
At a rally last week in Dallas, reporters observed hundreds of supporter allowed into the event without undergoing the same screening checks that are standard at smaller Obama events. In an effort to accommodate the 17,000-strong crowd, Secret Service agents ordered local police to stop searching each supporter individually who entered the event — this was at least the third time reporters have noted such an adjustment at large events in recent months.
"It looks like Obama is the Democratic front-runner, plus he's an African-American, so I'm not surprised by the protection, at all. In fact, I think it's good that they're tightening security," said David Katz, CEO of the Global Security Group, and a former FBI instructor and DEA special agent.
But the Obama campaign insists that no corners are being cut. "He has the best protection provided in the world. Every precaution is taken for an event," said a senior advisor to the Obama campaign.
Secret Service spokesman Ed Donovan would not discuss these specific events or any other details about the way Obama is being protected, however, he said, ""Many of the security measures that we utilize are not visible to the general public. And unfortunately we cannot discuss the other security methods that we utilize."
Even with large turnout at political rallies, the desire to move the crowd into an event does not override security, the Obama campaign says. "The Secret Service would never put anybody in a position of minimizing security for any other goal," the senior campaign advisor said. "They (the Secret Service) have one job to do and they do it 100 percent without cutting any corners."
"It is of the utmost importance now that the Secret Service provides the most rigorous protection for Sen. Obama," said ABC News consultant Fawaz Gerges, author of numerous books on national security and the terrorist threat. "It is a serious concern for many Americans in light of the historical precedents with Martin Luther King and President John F. Kennedy and Robert Kennedy."
To reporters traveling with the candidate, it seems there are visible signs that security around the senator is increasing. On a few recent occasions, armed snipers were spotted on rooftops, including at an outdoor rally in Wilmington, Del., and another in Clemson, S.C., in January. Reporters traveling with the candidate have noted an increase in protective measures, with background checks performed on reporters who have already been with the campaign on a daily basis for months.
"The most difficult thing for the Secret Service is to try to identify and to stop the person who's a threat," added Katz. "A lot these receiving lines, at these different venues, have areas with a lot of people pretty close to him, as with all these high-profile candidates. And I think that's probably why they're tightening it up — more people in line, more people in the crowd, more people around the senator, just to watch out for that type of tactic."
Secret Service spokesman Donovan adds: "We develop security plans and implement them in close cooperation with local law enforcement. And we don't deviate from those plans or change them in midstream because of crowd access issues."
In January, the head of Congress' Homeland Security Committee, Rep. Bennie Thompson, D-Miss., wrote to Homeland Security chief Michael Chertoff to make sure that adequate security was provided for Obama.
"The national and international profile of Sen. Barack Obama gives rise to unique challenges that merit special concern," wrote Thompson. "As an African-American who was witness to some of this nation's most shameful days during the civil rights movement, I know personally that the hatred of some of our fellow citizens can lead to heinous acts of violence.
"I remain concerned that the enormity of the 2008 election provides a terrorist — domestic or foreign — with a potent, high-profile target to make a statement," Thompson added. "We must be better prepared."
In response, Chertoff noted that the Secret Service had provided protection for Obama on 436 trips from May 2007 thru Jan. 11, 2008.
However, increased security can, in turn, create a whole new set of problems. At a rally in Cincinnati, the Secret Service ordered volunteers to block access to camera risers, normally reserved for the media. At a Jersey City event, reporters were held from departing the location because local police would not let media depart until Obama had left the premises.
Despite the complications, Obama seems to have built strong relationships with his security detail. As ABC's Sunlen Miller reports, when Obama has an event in the hometown of a Secret Service staff member, Obama likes to make special mention of the native son. Plus, the Illinois senator often plays basketball with his security guards — he even gathered with them to watch the Super Bowl earlier this month.
Obama's rival for the Democratic nomination, Sen. Hillary Clinton, D-N.Y., has also been guarded by increased security lately. Clinton, as a former first lady, is certainly no stranger to Secret Service protection. But as this campaign has gone on, the security seems to have grown as well.
At her recent campaign stops in Virginia, bomb squads, trained dogs, and wand-wielding security members all protected the New York senator. Reporters traveling with the candidate have also noticed stepped-up safety measures, including additional security sweeps of the campaign bus.
In their dedication to prevent a tragedy involving the politicians, security teams are themselves at risk. Last week in Dallas, Sr. Cpl Victor Lozada-Tirado, a police officer escorting the Clinton campaign motorcade to an event there, died in a motorcycle crash.
"We can't have a rally," Clinton later told an expectant crowd in neighboring Fort Worth, acknowledging the accident. "It would not be appropriate for me to take this opportunity as I had planned to be with you to talk about the election."
Obama said that Lozada-Tirado had previously helped the Obama campaign during their stop in the Dallas area, as well.
"We all have security details whenever we go to a particular city, and Sen. Clinton and I have Secret Service, but it's all done in cooperation with local law enforcement, and oftentimes we get motorcycle details who help set up motorcades and ease traffic when we're traveling into a city and out of a city," Obama said. "It's a reminder of the outstanding work that law enforcement does for us each and every day."
ABC News' David Wright, Sunlen Miller, Jennifer Duck and Eloise Harper contributed to this report.