TWILIGHT FOR SEN. CRANSTON

Alan Cranston, the only Democrat in California history who was elected to the U.S. Senate four times, is in the twilight of a long and generally memorable career of public service. His political sun is not going down because he has been found guilty of anything.. ..It is setting because he has been found wanting by voters.

A Times poll found this week that big majorities are suspicious of his relations with Charles H. Keating Jr., a high-rolling financier whose failed Lincoln Savings & Loan of Irvine may wind up costing taxpayers more than $2 billion to protect its depositors. Nearly 80% of the people who were asked think Cranston was wrong to take campaign contributions from Keating and then argue Keating’s case to federal regulators who were trying to take over Lincoln Savings before it collapsed.

Cranston, 75, is a truly global thinker--a rare condition in American politics--who cares deeply about such issues as arms control and the plight of veterans. He is a gifted organizer who helped guide his party back into prominence in the 1950s and who astonishes his fellow senators with his ability to predict the way they will vote, a trick he performs often as the Senate’s Democratic whip.

But he also has a rare, if not unique, attitude toward fund-raising. Where most politicians put reaching for a campaign check on a par with walking a plank, Cranston once told The Times that he enjoys gathering cash to promote his and his party’s causes.

Cranston gathered more than $900,000 from Keating, some for his own campaigns but most of it to promote voter registration, a program now being investigated both by the FBI and the Internal Revenue Service.

Cranston says the voters have been confused by wild, unfounded charges growing out of the Lincoln Savings scandal, and that once people understand what really happened, they will come around. He may be right, but he cannot count on that. The senator is not the only politician who carries a smudge where he came in contact with Keating. Four fellow senators have the same problem, as does Gov. George Deukmejian, a Republican. The governor, too, denies wrongdoing, but he has received $153,000 directly or indirectly from Keating, and the governor’s chief fund-raiser is also a lobbyist for Keating. Voters in The Times poll were very suspicious about that, too.

Deukmejian announced some time ago that he would retire next year, at the end of his second term, for reasons that had nothing to do with the Keating scandal. Cranston might well give thought to emulating the governor and bowing out when his own term ends in 1992.