Proceed with caution.

That, in essence, is the advice that the terrorism experts I know have for President Bush and Congress when it comes to handling the recommendations of the Sept. 11 commission.

Because the trade-offs between organizational simplicity and bureaucratic resistance are complex and difficult, these experts are nearly unanimous in saying it's important to take the time needed to sort through all these questions.

Members of the commission, starting with Chairman Tom Kean of New Jersey and Vice Chairman Lee Hamilton of Indiana, are mounting a full-scale national campaign to have the package of proposals that were unanimously endorsed by the commission late last month adopted without change -- and soon.

They picked up one important ally in Sen. John Kerry, the Democratic presidential nominee. Kerry barely had time to read the recommendations before giving them his unqualified support. It suits his purpose to favor forceful action against terrorism, the one major issue where voters say they trust Bush more than the Democrat.

But those who have studied the issue with care over the years urge a more deliberate pace of decision making. "It is more important to do it right than to do it fast," former senator Warren Rudman of New Hampshire told me.

Rudman was the Republican co-chairman of a counterterrorism commission, along with former Democratic senator Gary Hart of Colorado, that warned the nation in January 2001 of exactly the kind of attack that stunned Americans eight months later. Their credentials as serious and committed activists against terrorism need no burnishing.

When I saw Hart in Boston during the Democratic National Convention, he was full of praise for the Sept. 11 commission -- but unequivocal about a few points. Referring to the suggestion that a new "intelligence czar" be named to ride herd on the CIA and all the other intelligence agencies, Hart said, "It would be a disaster" if the new official went into the Cabinet or onto the White House staff -- the latter being the commission recommendation.

"You have to have a clear organizational separation between those responsible for generating intelligence and those policymakers who are the consumers," Hart said. "You mix them and you will inevitably get political pressures affecting the quality of the information."

When Hart and I talked, Bush had not yet weighed in on the subject, but it turned out he agrees. The president said the new national intelligence director and his staff should be in their own unit of government, not part of the White House or the Cabinet. Keep them insulated.

But Hart voiced a second concern that has only grown since Bush expressed his views. "Unless the new man has control over the whole intelligence budget of government," Hart said, "you simply have added a new layer of bureaucracy and set it up to fail."

"Every past proposal," Hart said, rattling off a half-dozen such efforts during his Senate years and since, "has foundered on the refusal of the Pentagon to give up an inch of control of its own intelligence spending."

The numbers he cited are those I read regularly in the media: Of the roughly $40 billion a year the government spends collecting and analyzing intelligence, about 80 percent is lodged in the Pentagon.

Rudman told me that as a practical matter the military would fight to the end to keep control of "tactical intelligence," the specific data that allow it to plan battles and monitor their progress. But he said the generals have a weaker case for running their own strategic intelligence operations.

The president has left this vital area murky, saying only that as he envisions it, the new director would "coordinate" the budgets of the CIA and 14 other intelligence services. But as any good bureaucrat knows, there is a world of difference between "coordinating" government operations and "controlling" them.

The impression is that Defense Secretary Donald Rumsfeld defended his turf very well during the internal administration debates over the Sept. 11 commission and came away with the president's support. Now it will fall to Congress to see if the Rumsfeld-Pentagon viewpoint prevails -- and, if it does, whether there is any point in just creating a new title and a new office in government.

As with most issues, what makes this one hard is that there are legitimate considerations tugging in different directions. But the stakes here are very high -- the safety of the nation. Congress needs to take the time to get it right.

davidbroder@washpost.com