Sen Lowell Weicker, who entered the crowded run for the Republican presidential nomination two months ago describing himself as "the longest shot in the field" made his candidacy the shortest of the year today by dropping out of the race.

The Connecticut Republican said his decision was based on a poll showing that he is well behind former president Gerald Ford and Ronald Reagan in his home state.

"any way you cut it now, it's third place and third place in this business isn't good enough," Weicker told a press conference in Hartford. "i can't go ahead and ask New Hampshire and Vermont and Florida to support me if they won't in my own state."

The same poll also showed that his popularity as a senator has dropped since his March 12 announcement of his presidential candidacy. "i cannot accept any further loss of support among the constituency I have worked so hard and so long to build," the two-term senator said. His favorable rating has slipped from 51 percent a year ago to 45 percent, he said.

"running for president of the United States is a monumental task. Connecticut voters may correctly assume that such a campaign exerts a distracting effect on a senator, no matter how dedicated he is to his senatorial responsibilities," Weicker said.

The withdrawal of Weicker, who gained national recognition as the youngest and most outspoken member of the Senate Watergate committee, leaves six announced candidates for the 1980 Republican presidential nomination: former Texas governor John Connally, former CIA director George Bush, Sen. Robert Dole of Kansas, Rep. Philip Crane of Illinois, former Minnesota governor Harold Stassen and businessman Benjamin Fernandez of Los Angeles.

The men running ahead of Weicker in Connecticut, ford and Reagan, plus Sen. Howard Baker of Tennessee and Rep. John Anderson of Illinois are prospective candidates.

Weicker announced his withdrawal on his 48th birthday and said that he alone was responsible for his poor campaign showing.

He began the race at odds with the Republican party regulars in his own state and elsewhere trying to stake out a position to the left of other candidates that would appeal to Democrats and independents.

Although this flies in the face of conventional ways to win the party's nomination, Weicker did not attribute the failure of his presidential plans to his lack of Republican support.

The millionaire senator also said that raising campaign funds had not been a problem during his short campaign.

Weicker entered the race throwing a series of barbs at his GOP opponents, calling them an uninteresting group.

He left the race without mentioning those still running, and gave no indication whom he would support for the Republican nomination. CAPTION: Picture, Sen. Lowell Weicker withdraws: "Any you way cut it, it's still third place." AP