It is possible that some of the changes were the unintended consequences of the rushed legislative process just before this month’s Congressional recess, rather than a purposeful effort by the administration to enhance its ability to spy on Americans.

“We did not cover ourselves in glory,” said one Democratic aide, referring to how the bill was compiled.

But a senior intelligence official who has been involved in the discussions on behalf of the administration said that the legislation was seen solely as a way to speed access to the communications of foreign targets, not to sweep up the communications of Americans by claiming to focus on foreigners.

“I don’t think it’s a fair reading,” the official said. “The intent here was pure: if you’re targeting someone outside the country, the fact that you’re doing the collection inside the country, that shouldn’t matter.” Democratic leaders have said they plan to push for a revision of the legislation as soon as September. “It was a legislative over-reach, limited in time,” said one Congressional Democratic aide. “But Democrats feel like they can regroup.”

Some civil rights advocates said they suspected that the administration made the language of the bill intentionally vague to allow it even broader discretion over wiretapping decisions. Whether intentional or not, the end result — according to top Democratic aides and other experts on national security law — is that the legislation may grant the government the right to collect a range of information on American citizens inside the United States without warrants, as long as the administration asserts that the spying concerns the monitoring of a person believed to be overseas.

In effect, they say, the legislation significantly relaxes the restrictions on how the government can conduct spying operations aimed at foreigners at the same time that it allows authorities to sweep up information about Americans.

These new powers are considered overly broad and troubling by some Congressional Democrats who raised their concerns with administration officials in private meetings this week.