U.S. intelligence officials say the political conventions represent a high profile target for terrorists. Homeland Security Secretary Tom Ridge recently told reporters that al-Qaida may want to replicate the bombing attacks carried out during the Spanish elections in March.

"Credible reporting now indicates that al-Qaida is moving forward with its plans to carry out a large scale attack in the United States in an effort to disrupt our democratic process," he said.

To combat the terror threat, security will be at an all time high at both the Democratic Convention in Boston and the Republican Convention in New York City at the end of August.

In Boston, local police are being assisted by bomb-sniffing dogs, harbor patrols and aircraft surveillance to ensure the safety of the thousands of delegates who will attend the convention in Boston's Fleet Center arena.

"We have put a lot of plans in place for this convention," said Boston Mayor Thomas Menino. "One of the unique things about our convention is that we are so close to an interstate highway, I-93, which is two-feet away from the Fleet Center [convention hall]. So we have to be more vigilant than anybody else has to be."

Beyond the political conventions, Homeland Security Secretary Ridge says U.S. officials are convinced terrorists may be targeting the election process right up through Election Day on November 2.

"Now, based on the attack in Madrid, and we have had several conversations about that, as well as recent interdictions in England, Jordan and Italy, we know that they have the capability to succeed and they also hold the mistaken belief that their attacks will have an impact on America's resolve," he said.

That concern prompted some discussion within the administration about the possibility of postponing the election should a terrorist attack occur.

Some opposition Democrats in Congress suggested the Bush administration was raising the security fears for political purposes. Among them was Senator Barbara Boxer of California.

"And with our men and women overseas literally dying for the rights of other people to vote, how could we even consider this, postponing the election," she asked.

Legal experts warn that postponing the election in the event of a terrorist attack would be problematic.

"To let one area of the country vote on a different day, after the rest of the country had voted, when they would almost certainly know the likely outcome of the election otherwise, distorts the results of the election," said Norman Ornstein, who is with the American Enterprise Institute in Washington.