As expected, Republicans are bringing tough questions for intelligence officials and the Obama administration on the politically sensitive topic of how to deal with suspected terrorists -- as enemy combatants or as criminals.
The two-day hearings range far beyond the attempted Christmas Day attack, as Republicans made clear Tuesday.
Sen. Jeff Sessions, R-Ala., who is the ranking Republican on the Senate Judiciary Committee, said he would use the hearing on the botched Northwest Airlines attack to draw a distinction between anti-terror policies under President Bush and those under President Obama.
The hearing will "provide a forum to discuss the national security policies of this administration, policies that I believe are moving us back toward the failed approach in place before 9/11," Sessions said Tuesday.
FBI Director Robert Mueller is on the hot seat today before the Judiciary Committee. He told the committee this morning that al Qaeda's terror network is emerging in Pakistan, Yemen and the Horn of Africa as the United States dismantles the group's operations in Afghanistan, according to The Associated Press.
It has been nearly a month since student Umar Farouk Abdulmutallab allegedly tried to bomb the trans-Atlantic Northwest flight Dec. 25. The Nigerian student sits in federal custody in Michigan after pleading not guilty to terrorism charges.
But today marked the first opportunity for lawmakers to publicly grill bureaucrats and administration officials on the incident.
Another hearing, scheduled for Thursday by the Senate Intelligence Committee, is classified and closed to the public and the media.
But, clearly, domestic attacks have taken center stage.
"Rewinding the clock to Sept. 10  will not deter Islamist militants. It will only embolden them," Sessions said.
"We should be building on and perfecting the security apparatus we put in place after 9/11,not tearing it down," he said in a preview of his hearing, arguing that Americans should have been more attuned to the terror threat even before 2001.
"We must remember that terrorists started their war on us before the Patriot Act, before Guantanamo Bay, before the wars in Iraq and Afghanistan, before even 9/11. In the 1990s, terrorists struck American embassies in Kenya and Tanzania, the USS Cole, and launched their first attempt to destroy the World Trade Center," Sessions said. "It was in 1998 that Osama bin Laden issued his call to war against the West."
Abdulmutallab was not yet a teenager in 1998, but the government's case against him in federal court in Michigan has been roundly criticized by Republicans, who argue that attempted acts of terror should be treated as part of a war and not law enforcement matters.
"They have given terrorists Miranda rights instead of tough interrogations, and have shipped foreign war criminals to American communities for civilian trial," Sessions said.
Other Republicans likely to make noise at the hearings include McCain, who sits on the Homeland Security Committee, and Sen. Lindsey Graham, R-S.C., a member of the Judiciary Committee. Both had criticized Obama for his decision to move terror detainees from Guantanamo Bay to the United States for trial in civilian court instead of by military tribunal.