That much is clear. Article 22 of the pact -- since renamed the Strategic Framework Agreement -- stipulates there will be no detentions without a warrant issued by an Iraqi judge except in combat or imminent-danger circumstances. The same rule governs searching of homes and other premises.
What isn't clear and what's vexing U.S. troops implementing the rule ahead of the official start date are the nuts-and-bolts issues of who, what, where and how.
"Our job, first off, is to figure out how the (Iraqi) system is supposed to work in obtaining a warrant," said Maj. John James, a Prosecution Task Force team leader from the 4th Division's 3rd Brigade Combat Team. "We engage with the Iraqi judges, engage with the judicial investigators, with the police, with the Iraqi army to see what venues (to get a warrant) work, what avenues of approach are going to work for us.
"Things have not been codified at the highest levels of the Iraq government on down … but we're making our way ahead."
The 4th Infantry Division, which operates in Greater Baghdad, decided in October to begin implementation of warrant-based detentions and searches from Dec. 1, a month ahead of the effective date of the unfinalized Status of Forces Agreement that's replacing an expiring U.N. mandate for U.S. presence in the country.
Prosecution Task Force teams were established all the way down to battalion level. The teams work in conjunction with Iraqi Security Forces -- army, local police and Ministry of Interior national police -- to identify investigating judges in each of the city's districts and subdistricts who have the authority to issue warrants in terrorism-related cases and who have the will to do so.
In the Iraqi legal system, there is one special court that deals with such cases. But the Americans later learned some investigating judges -- a special category of court officer who issues criminal warrants -- in other courts also could issue the paper.
Most judges encountered so far fear revenge targeting by extremists and don't want to be seen meeting with Americans. Iraqi Security Forces personnel are acting as go-betweens in identifying the judges, establishing contact with them and gaining their cooperation, PTF officers said.
Another part of the puzzle is sorting out differing evidential criteria. Some judges require just one detailed witness statement as part of an evidentiary packet. Others require two or more. Some judges will accept fingerprints lifted, for example, from an unexploded bomb or seized document as part of a probable cause evidentiary packet, but others will not.
"A major difficulty is getting the kind of evidence that we can give to Iraqi judges to look at," said Maj. Rana Wiggins, a 3rd Brigade Combat Team legal officer. "We can't give them any classified information (to protect intelligence sources and methods). But there are people out there who know, who see things. Of course, they are afraid and not coming forward, but that's something we can work with the ISF on, getting out there, getting the word out that we're looking for information on a particular person."
Wiggins said ISF are proving invaluable in filling in the blanks. The ISF's on-the-ground contacts help identify suspects, track down witnesses and obtain their statements. They also transport witnesses for required questioning by investigative judges and arrange non-courthouse venues for the interviews to safeguard participants.
Several warrants already have been issued after U.S. troops gave preliminary evidence to Iraqi police or soldiers with whom they normally work, Wiggins said. Those Iraqis ferreted out witnesses -- their identities are number-coded through most of the process for their protection -- and found additional evidence needed before giving the packets to judicial authorities.
Efforts are beginning to produce positive results. Soldiers of the 3rd Brigade Combat Team in East Baghdad now have more than 60 warrants in hand. At least 10 of those are warrants the Americans applied for through their Iraqi counterparts, and more are in the pipeline. The rest are legacy warrants -- those the Iraqis had obtained earlier and which can be used by U.S. troops. Among the wanted are members of al-Qaida, responsible for most of the car bombings and suicide attacks in East Baghdad, and Iranian-backed Shiite "Special Groups" such as Kataib Hizbollah, Asaib al-Haqq and Abu Dura.
Correct identification of those suspects is time-consuming. Names and spellings of names -- always a problem because of Arabic-English transliteration -- as well as pseudonyms are checked against Iraqi lists; known addresses are verified and photographs when available compared.
"Sleep, what's that?" James said.
PTF members acknowledged the new restrictions have a downside. No warrant, no arrest. U.S. troops at checkpoints, for example, who see a terror suspect or other suspicious individual in a vehicle but don't have a warrant on him will simply have to let him go unless he poses an imminent danger to their safety, commits a legal offense in front of them or is in illegal possession of a weapon.
"Our hands will be kind of tied with that. But we have to respect Iraqi law. That's what's required, and that's what we're going to do," Wiggins said.
2014: The Year in Music [PHOTOS]