The Connecticut Supreme Court ruled Friday that Gov. John G. Rowland must testify before a committee considering his impeachment.

In a 5 to 2 ruling, the court upheld an earlier decision by a lower court judge and dismissed the governor's arguments that the legislature was intruding on the separation of powers among branches of government by ordering him to testify.

Rowland is under investigation for accepting gifts from friends, state contractors and employees. He is also the subject of a federal corruption investigation. The three-term Republican has said he provided nothing in return for the gifts and has not compromised his office.

Ross Garber, the governor's legal counsel, said he plans to discuss the ruling with the governor before deciding whether Rowland will appear before the committee.

Lawmakers said if Rowland ignores the subpoena and decides not to testify, they will not compel him to appear.

"I am hoping the governor will choose to cooperate with the committee," said Rep. Arthur O'Neill, a Republican who is co-chairman of the House Select Committee of Inquiry.

If the committee recommends the articles of impeachment and the full House approves them, Rowland would have to temporarily step down as a Senate trial begins. Lt. Gov. M. Jodi Rell would run the state in the interim. The committee faces a June 30 deadline to make a recommendation.

Garber argued that the subpoena "treats the governor as a subservient officer." He said Rowland would be "hauled in" to testify for an unknown amount of time about an unknown number of subjects -- a move that could encourage future lawmakers to demand a governor testify at their whim on more mundane issues, such as the budget.

Cynthia Arato, a private attorney hired by the inquiry committee, said Rowland claims he has absolute immunity against being compelled to testify -- a special immunity she said does not exist. Arato pointed out how the courts have ruled that the judicial branch of government can subpoena a governor to testify, and said the legislature should receive the same treatment.

"We're all co-equal branches," she said.

The dissenting judges, Chief Justice William Sullivan and Justice Peter Zarella, said court intervention is unnecessary.

Gov. John G. Rowland is under state scrutiny for accepting gifts and faces a federal corruption inquiry.