Washington (CNN) -- U.S. park officials came under fire during congressional hearing Tuesday as Republican lawmakers scrutinized the "Occupy" encampments, which have persisted in the capital for nearly four months.
The main issue: Are the encampments in violation of the law?
Led by a subcommittee of Rep. Darrell Issa's House Committee on Oversight and Government Reform, the conservative congressman articulated his opposition to what he said is the illegal use of city grounds.
"If we don't find a uniform and predictable set of rules for the future, then we put the District of Columbia in a very untenable position," said Issa, a California Republican. "They find themselves unable to predict who will sleep where and what they will and won't be able to do."
The congressional hearing was the first in what is expected to an ongoing debate into whether it is legal for the protestors to continue to eat, sleep and protest in the U.S. capital's squares and plazas .
The Occupy movement, which began in New York City in September, was the catalyst for similar protests in hundreds of cities.
In Washington, two sites have prevailed: Freedom Plaza and McPherson Square.
The National Parks Service maintains that the Occupy DC protesters are maintaining 24-hour vigil, which is legally permissible. But some members of the subcommittee disagree, taking aim at the director of the National Park Service, Jonathan Jarvis.
"Mr. Jarvis is completely out of line; it is not his job to interpret the Constitution," said Issa. "He has to execute law. It's for men and women in black robes here in Washington to make that determination."
The situation has also made Jarvis a hero among occupiers and their advocates.
The committee's ranking Democratic member, Rep. Elijah Cummings of Maryland, praised Jarvis for his 35 years of service.
"You really understand what it means to have freedom of speech," Cummings said.
Jarvis read from a prepared statement Tuesday, explaining the Park Service's approach to maintaining safety at the site.
"This is unprecedented, and we're working through it," he said. "We have developed a rapport at the site with demonstrators," he added, explaining that occupiers have come to work with the agency to assist in maintaining the site's safety.
While the hearing was not meant to debate the merits of this protest, the constitutionality of the Occupy Wall Street movement is entangled in the fate of Occupy DC at McPherson Square.
One solution favors consolidating the two Occupy sites in Washington to Freedom Plaza, which would significantly diminish the size of the protest.
The 2-square-acre park is one of the smallest under the Parks Service's jurisdiction.
CNN's Paul Corson contributed to this report