July 12, 1981

Nothing in their national experience - not soccer hooliganism or the ''mods'' versus ''rockers'' rumbles of the 1960's - prepared Britons for the fury and scope of youth violence that erupted in urban neighborhoods throughout the country last week. ''Most of us did not think these kinds of things could happen in our country,'' Prime Minister Margaret Thatcher confessed, after youths wielding bricks, gasoline bombs, spades and machetes left parts of the already dilapidated Toxteth section of Liverpool looking like it had been through the blitz. ''The veneer of civilization is very thin,'' Mrs. Thatcher added. Nearly 300 people, almost all of them police, were injured and more than 500 rioters were arrested.

President Reagan, who is to meet in a week with the leaders of the major industrial democracies in Ottawa, will urge them to give him time to bring down the high American interest rates that are choking the economies of Europe, Administration officials say. Mr. Reagan also plans to urge the leaders to consider exercising greater control over the transfer of advanced technology to the Soviet Union and to discuss the wisdom of sustaining trade with the Russians at present levels, given the concern about Soviet behavior around the world. In addition, Mr. Reagan plans to commit himself to aiding underdeveloped countries but to question the emphasis placed by some American allies on direct assistance, as opposed to the Administration emphasis on loans and investments from the private sector. A Chance to Get Acquainted However, these priorities, disclosed by Administration officials in interviews, are described as secondary to the main objective for Mr. Reagan as he prepares for his first summit conference. That objective is simply for Mr. Reagan to become better acquainted with his fellow world leaders - many of whom are at least as new to their jobs as he is - and to demonstrate to Americans that he can be as comfortable discussing his policies abroad as he is at home.

W HEN French social philosopher Alexis de Tocqueville arrived in the United States 150 years ago he marvelled at this country's knack for business. ''The greatest industrial undertakings are executed without difficulty,'' he wrote. Would he make the same claim today? It would clearly be more difficult: Of late, America's tradesmen have seemed more inclined to buy than build. The latest merger bandwagon, which got rolling in l975, is gathering speed and shattering records that have been untouched since late l968 when corporations spent more than $43 billion on acqusitions. Du Pont twitches its brow and puts $7.3 billion up for Conoco. The Fluor Corporation nods and spends $2.7 billion for St. Joe Minerals. Seagram keeps raising its weary hand to try to spend $3 billion. The rush to merge is the result of continuing inflation that often tends to make buying things more profitable than productive investment, tepid economic growth which curbs consumer and industrial demand for new productive capacity, and a stock market that has severely undervalued the assets of many companies.

Like supporters and detractors of her Supreme Court nomination, Sandra Day O'Connor devoted the better part of this week to a review of the state legislation and judicial decisions that constitute the record of much of her public life. With her office at the Arizona Court of Appeals here overflowing with congratulatory bouquets, her desk cluttered with papers and files, and her law clerk, husband and friends helping with the review, Judge O'Connor looked up at a brief break yesterday morning to sigh, ''It's a nightmare.'' ''Fifty years is a long time,'' she said, ''and it's hard to remember everything you did.'' Differences of Temperament The review is far from complete, but the woman, public and private, who has so far emerged from an examination of of those records, and from conversations with friends, colleagues and adversaries, is by political instinct, judicial philosophy, economic standing and personal temperament both similar to and different from the constituency that elected Ronald Reagan President. Judge O'Connor emerges as a sometime conservative with a moderate, even progressive streak, a determined woman but not a dogmatic one. President Reagan described her as a ''person for all seasons,'' but she appears to be something less than the advocate that other supporters, including many in the feminist movement, have made her out to be. At the same time she is clearly more complex than her detractors, including Moral Majority and the anti-abortion lobby, have suggested.

THE state's 5,200 Indians, sometimes called the ''the invisible minority,'' have come into view in recent weeks, the result of a legal victory that guarantees the establishment of a new reservation and opens the way for the expansion of several others, but also of a legislative defeat that leaves the Indians for the first time in 300 years without an official liaison at the State Capitol. The legal victory was a ruling by the United States Supreme Court that the Mohegans, Connecticut's only indigenous tribe without a reservation, were protected by the 1790 law under which the tribe sought to reclaim their land. The decision prepared the way for negotiations involving more than 2,500 acres of land in Montville, a town of 17,000 people about 10 miles north of New London. The land, currently owned by the state, includes the Fort Shantok Indian burial grounds, a plot one Mohegan chief, Courtlandt Fowler, called ''the most important thing.'' The decision also appeared to enhance the reclamation efforts already under way by two other Connecticut tribes - the Schaghticokes, who are suing to reclaim 1,600 acres around their reservation in Kent, and the Mashantucket Pequots, who are fighting for 800 acres near Ledyard - and to set the stage for another claim by the Mohegans for land in the area between Norwich and New London.