May 17, 1986

Senator Alfonse M. D'Amato, who had to bus Long Island supporters into Manhattan when he announced six years ago that he would run for the Senate, declared his candidacy for a second term yesterday surrounded by Republican and Conservative party leaders and Robert Dole, the Senate majority leader. ''We have come a long way,'' Mr. D'Amato, a Republican, said several times in an announcement ceremony at the Women's National Republican Club, 3 West 51st Street. Mr. D'Amato has been bolstered by polls that show him an early strong favorite, and the gathering yesterday was more a political rally - with band, straw boaters and signs - than the usual announcement news conference. Drugs a Key Issue The event also departed from the tradition of such news conferences, as the Senator continually emphasized the need to combat ''the scourge of drugs'' rather than discussing the customary national and international issues. The Senator, who has been criticized for paying too much attention to local issues, said the drug issue was one that should have national attention because it crossed state and national boundaries. ''If there is anything I want to dedicate myself to in the next six years, it is that,'' he said.

The overhaul of the nation's tax laws now before Congress marks a reversal of decades of growing Government and special-interest influence over how people and businesses use their money. The tax law changes, in particular those that the Senate Finance Committee adopted unanimously last week and that President Reagan has endorsed, mean that the tax system would play less of a role in shaping society and its economic foundations. This is in part because the changes would diminish the tax code's incentives to steer income to certain activities, and in part because it would let individuals keep more of their income, which they could then feed into the economy as they wished. Just about all economists maintain that this would produce a sounder and healthier economy and, eventually, higher wages and lower unemployment. It leaves open the questions about prospects for the individuals, charitable organizations and businesses that the tax system helps protect and that an efficient economy tends to overlook.

The Attorney General's report on the social effects of pornography has drawn expressions of dismay and shock from some of the researchers on whose work the report's conclusions are largely based. The report, to be made public in July, states that exposure to pornography plays a role in causing ''sexual violence, sexual coercion or unwanted sexual aggression.'' A copy of the draft was made available to The New York Times earlier this week. In the 211-page introduction, the Attorney General's Commission on Pornography calls for Government action against the pornography industry, including stricter penalties for violation of laws on obscenity. But the researchers who provided key data for the report denied Friday that the panel had established a direct causal link between most sexually explicit material and any act of sexual violence.

Move over, New York. This prairie town of 19,800 in the Illinois Corn Belt is claiming the title of Bagel Capital of the World. Soon after the huge Lender's Bagel Bakery on State Route 121, 180 miles south of Chicago, goes into full production later this month, it will be churning out a million bagels a day. And with bagel consumption nationwide rising rapidly, executives of Lender's, the nation's largest bagel baker, expect the plant to be producing two million of the rolls with holes a day in two years - which would make it the world's largest bagel bakery. ''What we're seeing is the Americanization of the bagel,'' said Mark Gaynor, managing editor of Bakery Production and Marketing, an industry magazine.

Two teen-age mountain climbers who lived through a three-day ordeal beneath a deep mantle of snow on Mount Hood apparently survived because they were the closest to the top of a snow cave that eight climbers had dug for shelter, a doctor said today. The six others died. The survivors ''were at the top of the pile of bodies,'' Dr. William B. Long, of Emanuel Medical Center, said. ''Perhaps their bodies were better insulated from the cold,'' he added, suggesting that the six below them had absorbed the worst of the cold from the snow. Heat would also rise to the top of cave, which was covered by a tarpaulin and four feet of snow.