Last December a key administration official recommended that President Bush's son Neil sign an ''administrative statement'' or ''consent order'' agreeing not to serve as a savings and loan director or official, thus ending his vulnerability to conflict-of-interest charges in the S&L scandal growing out of his directorship of the Silverado Savings and Loan.

The rough equivalent of an anti-trust consent decree, the statement might well have exempted Bush from acknowledging any illegal acts at all. But Neil and his father's close friend, former Democratic representative Thomas (Lud) Ashley, ruled that out.

Ashley told us this week, months after the proposal was rejected: ''Neil's integrity is not what they are paid to protect at the White House. They are paid to protect the president's political butt.''

One result of that decision is a seeming lack of White House commitment to protect Republicans and funnel the erupting S&L volcano against Democrats. If so, it could be a windfall for the party most vulnerable in the nation's worst financial scandal, by keeping the spotlight on the young man whose rush to make his fortune has given the Democratic Party a priceless symbol in the blame game.

Democratic vulnerability comes from the well-publicized activities of former speaker Jim Wright, former whip Tony Coelho, former Banking Committee chairman Fernand J. St Germain and others. S&Ls became their campaign-fund milking machine. In the Senate, Democrats make up 80 percent of the Keating Five, who milked Charles Keating's Lincoln S&L.

Whatever the final disposition of Neil Bush's legal problems, lack of White House help to mute the danger from the allegations against him stuns the GOP. With Republican rank-and-filers still reeling from the shock of Bush's unexpected about-face on taxes, along comes the Office of Thrift Supervision to charge that Neil engaged in ''one of the worst kinds'' of conflict of interest. With other Silverado directors, he faces a possible $200 million recovery suit.

The December recommendation that Neil Bush sign a consent order also proposed that he engage a new law firm. One administration source told us that the decision by Ashley and Neil Bush to reject those proposals was also supported by the president's intimate friend, Treasury Secretary Nick Brady, who is convinced of Neil's innocence.

Admittedly, few political rules apply when the matter concerns a member of a president's close family. When a key aide of former president Carter recommended quick restitution of Carter's brother Billy's damaging loan from Col. Moammar Gadhafi of Libya, Carter agonized, then vetoed personal pressure on his younger brother. His decision was steeped in the deep-rooted, sometimes troubled relationship between the two brothers.

If any White House aide was able to push or pull George Bush in the matter of Neil Bush it is a secret. ''I will not discuss that matter in any way at all,'' a highly trusted White House aide said privately. The clear implication: talking about Neil Bush's alleged financial peccadilloes is an Oval Office no-no.

That comports with the public see-no-evil, hear-no-evil silence on the part of Republican political chiefs. ''There is no antenna up, no radar turned on for Neil Bush,'' one of the party's key strategists told us. As a result, the job of Edward J. Rollins, co-chairman of the National Republican Campaign Committee, becomes that much harder. Rollins has been counting on public fury against the Democrats to help him elect Republicans on Nov. 6.

The velocity of this public fury is astounding. After the single July 9 session of his anti-trust subcommittee's probe of 15 failed Texas S&Ls, Sen. Howard M. Metzenbaum (D-Ohio) told us his office received ''hundreds'' of phone calls from infuriated citizens with tips on similar S&L outrages.

Up to now the target seems shrouded, but voter sentiment may crystallize against a single party. Thus Republican leaders are pushing the White House to help in frontal attacks against Democrats alleged to be tainted by the S&L scandal, including Sens. Alan Cranston (Calif.) and Donald Riegle (Mich.), two of the Keating Five. ''We'll take it right into the states,'' said a White House aide.

But it is Neil Bush's crusade for innocence that is making the headlines. If the Democrats can cash in on this young man who went on Silverado's board five years ago at age 30, with no money and no experience in a director's fiduciary responsibility, George Bush and the Republican Party will pay the bill.