ALAN CRANSTON, a senior member of the United States Senate and one of the most durable politicians in California history, faces what some say is an insurmountable political challenge. Even though the veteran Democrat is not up for reelection until 1992, there is a growing feeling among political professionals - including some Democrats - that he will not be able to win a fifth term in the wake of controversy over his involvement in the Lincoln Savings & Loan scandal.
While Cranston says he is innocent - and that he intends to run again - analysts contend it will take plenty of political acumen just to survive his current term.
``I think there is zero chance he could plausibly run for reelection,'' says one Democratic activist, who requested anonymity. ``But out of respect for what he has accomplished, I think there are a lot of people who would like to see him serve out his term.''
``I don't know what he can do to turn it around,'' says Joe Scott, who edits a political newsletter.
Cranston is not alone. The savings and loan scandal is producing varying degrees of political trouble for each of the quintet of senators involved. The Senate Ethics Committee is investigating their ties to Charles Keating Jr., a Phoenix developer who ran the failed Lincoln Savings & Loan, in Irvine, Calif.
The lawmakers met with federal regulators on Keating's behalf after accepting large political donations from him. The Ethics Committee wants to know what motivated the lawmakers. Each says it was nothing nefarious.
Still, the Lincoln debacle alone will cost taxpayers an estimated $2 billion - a significant chunk of the estimated $150 billion S&L bailout. Lincoln's high cost is attributed partly to regulator delay in taking it over after the senators intervened.
In Ohio, Sen. John Glenn (D) seems not to have suffered irreparable damage to his ``Mr. Clean'' image. The response has been more pointed to questions about Sen. Donald Riegle Jr. (D) of Michigan, analysts there say.
In Arizona, where the ailing thrift industry has affected thousands of depositors, Sens. Dennis DeConcini (D) and John McCain (R) face formidable image-repair work. A poll last month by the Phoenix-based Behavior Research Center showed a significant drop in support for both.
``The Arizona public is in a state of shock,'' says Earl de Berge, of the Behavior Research Center. ``Financial institutions are in retreat. The economy is in serious difficulty. Senators are under attack. Voters are hard pressed to know where to put their trust.''
Two local political activists are considering launching a joint recall effort against the two men. While analysts give the idea little chance of success, it would help keep the issue in the public eye.
``I think if the election were held next year for either of them, they would be in deep chocolate,'' says Jim West, a Phoenix-based political consultant. ``But both have a couple of years to redeem themselves.'' (McCain's seat is up in 1992, DeConcini's in 1994.)
Perhaps the biggest rabbit punch, though, has been to Cranston, the Senate's Democratic whip.
Cranston accepted the most money from Keating - more than $900,000. And both Cranston and DeConcini are under particularly close scrutiny because, unlike the others, they continued representing Keating even after being told a criminal investigation of Lincoln had been recommended. Some say Cranston's initial lack of damage control has hurt, too, though he has been more aggressive recently.
Even if the septuagenarian were exonerated in the affair, analysts say its taint, coupled with his age and his last narrow election victory, makes him a GOP target in 1992. A recent Los Angeles Times poll showed Cranston's favorability rating down 24 points in an eight-week period.
``Even without the Keating affair, the odds were not in his favor,'' says California pollster Mervin Field.
``It is not a case of Democrats abandoning him,'' says a veteran Democratic consultant. ``It is a case of recognizing political realities.''
Cranston, for his part, will have nothing to do with polls or pessimism. The senator says he does not believe his standing is as bad as surveys suggest, nor that reelection in 1992 is hopeless.
As for involvement with Keating, he admits to intervening in a protracted investigation of Lincoln - not just for one constituent, but for the institution's 140,000 California depositors. The aim was not to influence, just seek a speedy resolution, he says.
Cranston took from Keating $47,000 in direct contributions and $850,000 for voter registration efforts. The Federal Bureau of Investigation has reportedly expanded its investigation of Lincoln to include Cranston's voter-registration efforts.
Ironically, the senator's future depends in part on his continued fund-raising prowess. He already has begun soliciting for his 1992 reelection drive. Amassing a war chest early would presumably discourage would-be challengers - assuming he weathers this term.
While few Democrats are publicly saying he should quit after this term, talk grows in party circles of who might seek his seat.
The GOP, meanwhile, is murmuring over its own list. ``The Republicans are licking their chops at the kind of campaign they could run against Cranston,'' says Sherry Bebitch Jeffe of the Center for Politics and Policy at the Claremont Graduate School.