State Senate President Melvin A. Steinberg, embarking on a political high-wire act that could affect thousands of Maryland savings and loan depositors, today scuttled Gov. Harry Hughes' agreement to allow the sale of three thrifts to the Chase Manhattan Corp.

Steinberg's dramatic announcement that the Senate would not approve a $25 million payment to Chase that was part of the agreement came on the eve of a special session of the General Assembly that was to consider the transaction and stunned the Hughes administration, which was relying heavily on the sale of the thrifts to free $500 million in deposits and reduce any losses the state would have to cover if a buyer for those associations could not be found.

Steinberg, showing the considerable clout he wields by speaking alone for the 47-member legislative body he rules, spiked Hughes' plan at a critical time for the governor, who has all but announced he will run for the U.S. Senate in 1986.

Today's events signaled the second time this month that a pending agreement with a New York bank to save a failing savings and loan has collapsed, thwarting Hughes' goal to lead the state out of its fiscal crisis, which is now five months old.

Hughes and Chase officers said legislative approval of the deal would have given the 70,000 depositors of Merritt Commercial Savings & Loan of Baltimore, Friendship of Bethesda and Chesapeake of Annapolis virtually instant access to their money, which has been frozen or tightly restricted for five months.

Shortly after 7 p.m., Hughes banned all withdrawals at Friendship and Chesapeake for the next 20 days.

The deposit freeze came at the request of officers of those two thrifts, who feared a run by depositors after the Chase agreement collapsed. Withdrawals are already banned at Merritt.

A special session will still take place Thursday, Steinberg told a standing-room-only crowd of reporters and legislators in the ornate Senate lounge this afternoon.

Legislation to be considered will include allowing out-of-state banks to set up business in Maryland only if they acquire a troubled savings and loan.

Disappointed Chase Manhattan executives left the statehouse after Steinberg's declaration that the Senate would not approve the up-front $25 payment.

The payment from a thrift industry insurance fund was the sweetener for the New York banking giant to buy the debt-ridden Merritt, as well as Friendship and Chesapeake.

Many observers here said they believe Steinberg, a Baltimore County Democrat and an acknowledged master of legislative brinkmanship, announced the Senate's opposition to the Chase deal to give the state a better bargaining position in any future talks that might be held with Chase.

Steinberg said the key reason he opposed the cash payment to Chase was that the Senate never received enough detailed information about the arrangement or who would benefit from it.

"It's either the greatest game of 'chicken' or Chase takes a walk and a lot of people will be very mad at Mickey Steinberg," said one thrift industry lobbyist.

Chase Vice President Stanley Burns, like Hughes and House of Delegates Speaker Benjamin L. Cardin (D-Baltimore), expressed disappointment at Steinberg's action.

"In our view, the most appropriate thing for us to do is very gracefully depart from the scene," said Burns. "We can't make the deal work absent the financial help we've discussed."

Steinberg's blow to the Chase deal was easily the most dramatic event of the day, confounding dozens of legislators who are being pressured by constituents to free up deposits.

But the Senate president's action also set in a motion other events that added to an atmosphere of chaos and disarray:

Senate leaders began drafting legislation that would effectively nullify a measure approved earlier this year allowing out-of-state banks such as Chase to open branch banks one year after entering the state on a limited basis. That new measure is widely perceived as another way of goading Chase into renegotiating the thrift purchases, because the bank also was seeking expansion rights under the earlier law.

In the Economic Matters Committee of the House, a real estate expert who has managed Merritt's assets since May testified that while the sale to Chase was "an excellent deal," it also could provide Merritt owner Gerald S. Klein with two properties that could "It's either the greatest game of 'chicken' or Chase takes a walk and a lot of people will be very mad at Mickey Steinberg." -- S&L industry lobbyist generate at least $7 million in profit for Klein.

The potential profit for Klein has been a major stumbling block for Chase as it promoted its deal to legislators, who hold the Merritt owner largely responsible for the thrift's troubles.

"Concern has developed whether losses will actually be incurred," said Steinberg, alluding to the legislators' insistence that Klein gain nothing through the Merritt sale.

Chase officers and the Hughes administration launched an intense lobbying effort a week ago to convince the legislature that the state's $25 million price tag in the Chase arrangement was more than offset by removal of Merritt, Friendship and Chesapeake from the lengthy list of thrifts that have not received federal deposit insurance -- and whose losses the state government may have to cover.

Merritt, hampered by a portfolio that includes many poor loans and assets, could never obtain federal insurance on its own, according to state officials. Friendship, which lost $9 million in assets betwen March and September, and Chesapeake, which lost $1 million in the same period, would have an arduous time obtaining insurance, thrift industry experts say.

Chesapeake President Art Silber said he was stunned at Steinberg's action.

"They've just done a real job on the people of the state and increased the government's liability dramatically," Silber said.

"They can now add $75 million for Merritt, plus whatever losses are at Chesapeake annd Friendship."

Because of purchase agreements it reached with Silber and Friendship and the time needed for approval by the federal government, Chase had given the legislature an Oct. 19 deadline to act on its deal.

Chase officers told the General Assembly that speedy action was needed to stem what they described as "deteriorating" conditions in the Maryland's thrift industry.

"Our biggest concern has been deterioration, but that hasn't seemed to sink in," a senior Chase officer said late tonight. "We're not going to get tangled up in the political brouhaha. We gave it our best shot, and if it doesn't work, we'll move on."

Several depositors who attended Steinberg's news conference reacted grimly to the Senate president's announcement.

"We're the pawns in this process," said Bill Beanland, a Montgomery County resident who has more than $10,000 tied up in Community Savings & Loan, a Bethesda thrift that is frozen by state conservatorship. "We're an amorphous, sheep-like group of folks, but we thought we had won something in this Chase deal."