Updated

To many of President Bush's allies, it is time to free intelligence officials from "legislative purgatory" and get the CIA back in the business of effective interrogations of suspected terrorists.

That chance could come this week if the Senates takes up a White House proposal limiting the punishable offenses that CIA interrogators may face when questioning "high-value" terrorist suspects. Senate Majority Leader Bill Frist, R-Tenn., is expected to begin debate on the bill as early as Tuesday.

Get complete coverage in FOXNews.com's War on Terror Center.

Through omissions and legal definitions, the proposal could authorize harsh techniques that critics contend potentially violate the Geneva Conventions, which govern the treatment of war prisoners. These methods include hypothermia, stress positions and "waterboarding," a practice of simulated drowning.

The bill would keep in law prohibitions on war crimes such as rape and torture that are widely accepted as illegal.

The proposal would apply back to 2001 the Bush administration's standards for treatment of detainees. That would shield CIA personnel from liability under a 1996 law intended to uphold the Geneva Conventions, since the fight against terrorism began and harsher interrogation methods were approved.

Sen. John Warner, chairman of the Senate Armed Services Committee, has developed his own plan to address concerns he has related to the military commissions that would prosecute terrorism detainees. According to a draft copy of the bill, his legislation also may amend that 1996 law, the War Crimes Act.

President Bush sent his plan to Capitol Hill last Wednesday, the same day the Pentagon issued rules forbidding military personnel from using those same harsh techniques.

"The net effect is that at least some of the alternative techniques are rendered, in effect, lawful" for the CIA, said Martin Lederman, a Georgetown law professor and former legal adviser at the Justice Department during the Clinton administration.

Lederman and other legal experts, along with human rights activists, say the White House proposal would undermine the 1949 Geneva Conventions by providing a more narrow definition of objectionable treatment.

"I think that's the bombshell ... because no other country has done that," said Elisa Massimino, the Washington director for Human Rights First. "And once we do, we lower the floor and the whole structure could crumble."

But according to conservatives, the move was necessary to repair damage done to the White House's intelligence program since a Supreme Court ruling in June. The court ruled against Bush's claim that interrogators did not have to comply with the Geneva Conventions when dealing with members of al-Qaida.

The court's decision to grant suspected terrorists certain rights potentially exposed Americans to prosecution under the War Crimes Act. The result, conservatives say, was a profound cooling effect on the CIA interrogation program.

"We're interviewing, not interrogating," said Sen. Pat Roberts, chairman of the Senate Intelligence Committee.

Roberts, R-Kan., said in a recent interview that he believes intelligence officials are frozen in a type of "legislative purgatory." He said that keeps them from wanting to "walk up to the line, as has been the case before where we got 50 percent of our intelligence on what the terrorists were doing."

Tom Crispell, a CIA spokesman, declined comment on the agency's program.

According to recent public opinion polls, Roberts is not alone with his concerns. In an August poll conducted by Time, 55 percent of those surveyed said they support the harsh interrogation methods sometimes used to obtain information from prisoners in Iraq and Guantanamo Bay, Cuba. In a separate poll also by Time, 15 percent of respondents favored torture, even though it is against the law.

Such a willingness to be tough on terrorists could help Bush push a hard line on his legislation. At the same the president is asking Congress to amend the War Crimes Act and establish military tribunals to try detainees, he also wants lawmakers to approve the National Security Agency's terrorist surveillance program.

The effort is seen by many critics as an election-season push to expand his authorities to monitor suspected terrorists at a time when lawmakers from both parties are selling themselves as tough on terrorism.