Gov. Harry Hughes' plan for legislative reapportionment cleared two major hurdles today when a Senate committee and the full House turned down efforts to amend it.

Although the action bodes well for the future of the governor's plan, several legislative leaders said they expect more attempts to alter it because of an intensive lobbying campaign by Senate President James Clark, who is fighting to reunify the community of Columbia in his home base of Howard County.

Hughes split Columbia after the Prince George's County delegation argued that other options would not have preserved the county's level of political representation in the capital.

Clark's effort, the only serious threat to change the governor's proposal, was rejected by the Senate Constitution and Public Law Committee today along with 13 other amendments. Clark was optimistic last week that his lobbying efforts on the measure would be successful and blamed today's 5-to-3 defeat on the strength of Prince George's legislators on the committee.

After this defeat, Clark vowed to bring his amendment to the Senate floor for a vote. He has already met several times with senators from Montgomery County to ask for their support.

"That the Clark amendment has been the subject of intense discussion and negotiation for the past four days," said one Montgomery senator. "We thought we had a compromise but it all fell apart. We hope to work something out by next week."

According to Senate sources, the Montgomery delegation was prepared to support Clark on the floor "to help the Senate president save face," knowing that, even if the amendment was adopted in the Senate, the House would ultimately kill it. But, these sources said, Clark began lobbying members of the House as well, angering the Prince George's delegation and threatening the whole reapportionment process with being opened up to multiple amendments.

"We were willing to let him save face," one source said, "but once you open up Pandora's box you find a lot of worms in there."

The maneuverings in both the House and Senate reflect the political importance that many legislators attach to the process of reapportionment. The challenges to Hughes' plan were in most instances attempts to placate small groups of citizens in home counties by offering loud criticisms of the plan.

"They knew none of these amendments would pass," one delegate said after the House vote. "But they had to do it to look good at home."