A prominent criminal defense attorney in Albany is preparing to announce his candidacy against the Republican leader of the Senate, Joseph Bruno, who hasn’t faced a serious general election challenge since he was crowned majority leader in 1995.

Seeking to catch the wave of Democratic momentum following his party’s upset victory in an upstate Senate election last month, the lawyer, Brian Premo, says he’s convinced Mr. Bruno is beatable. “I have always believed that in our community, Joe is not as well-liked as he would like to believe and as others in the political arena might presume,” he said in an interview.

“People are tired of the dysfunction in Albany, and in particular of Joe Bruno. He wants to take credit for everything he thinks is good in government, and he wants to take no responsibility for everything we know is bad in Albany,” he said.

While the Republican electoral defeat and a revived federal ethics investigation into Mr. Bruno’s business dealings have raised questions about his political viability, the 78-year-old senator remains a potent force in his district — encompassing Rensselaer County and part of Saratoga County — where Mr. Bruno has steered hundreds of millions of dollars in discretionary aid and capital projects.

Mr. Premo, 48, sought to run against Mr. Bruno two years ago but was kept off the ballot by Democratic Party leaders in Saratoga after he missed a filing deadline to change his registration to Democrat from Republican.

The son of a machinist and one of 14 brothers and sisters, Mr. Premo lives in Brunswick, about four miles east of Mr. Bruno. He’s been in private practice for most of his career, representing a number of high-profile clients, including a rabbi who was charged with smuggling drugs into a federal prison.

Saratoga leaders have yet to endorse a candidate. The supervisor of Saratoga Springs, Joanne Yepsen, a Democrat, is also considering mounting a bid against Mr. Bruno.

The state Democratic Party has yet to determine its favorite candidate or the extent of its involvement in the race.

By backing a candidate against Mr. Bruno and providing financial support, Mr. Spitzer, who controls the party, would risk further inflaming his relationship with the senator.

Mr. Spitzer invited the majority leader to the governor’s mansion in Albany last Monday morning for a one-on-one conversation. The subject, according to one aide to Mr. Bruno, was about “working together,” something they have not done as of late.

Aides to the governor characterized the meeting as “cordial,” while aides to Mr. Bruno declined to describe the tone.

That Mr. Bruno, Mr. Spitzer’s most persistent critic, would be caught breakfasting with the enemy is a surprising development in a statehouse that was the setting last year for profane screaming matches between the leaders.

Messrs. Bruno and Spitzer had not been on speaking terms since allegations emerged last summer that the Spitzer administration sought to damage the majority leader by publicizing police records about his use of state helicopters for fund-raising trips to New York City.

The governor is reaching out to Mr. Bruno as budget negotiations between the Spitzer administration and the Legislature approach the final stages.

The Senate is expected to propose its fiscal budget on Wednesday. Aides to Mr. Bruno said it would restore Medicaid funding and suburban public school education aid that was slashed in the governor’s budget, and would eliminate several hundred million dollars in various fee increases and business tax “loophole closures” proposed by the governor. The Assembly today is presenting its own budget, which will include a 12% personal income tax hike on residents earning more than $1 million that is expected to raise $1.5 billion a year.

The Assembly budget also eliminates Mr. Spitzer’s proposed plan to sell two parcels of land near the Jacob K. Javits Convention Center, one at the north end and the other at the south end.

The Spitzer administration had already announced that it was suspending its plan to sell the northern parcel — between 39th and 40th streets — until it could work out an agreement with the Bloomberg administration and city lawmakers.

The budget is due April 1.