When President Reagan receives two lists of nominees for the new U.S. Sentencing Commission soon, it will mark the beginning of the end for an idea that has dominated criminal justice for a century: that prisoners can be rehabilitated.

The Comprehensive Crime Control Act of 1984 created the commission to establish guidelines to reduce the disparity in sentences received by federal prisoners who commit the same crime and have similar criminal records.

But the commission is also supposed to formulate guidelines that "reflect the inappropriateness" of imposing a sentence "for the purpose of rehabilitating the defendant or providing the defendant with needed educational or vocational training, medical care or other correctional treatment."

Civil libertarians and the Reagan administration agree that rehabilitation is not a valid reason for imprisoning a person. Though they acknowledge that some inmates will reform themselves, they cite studies showing no correlation between prison experiences and the tendency to commit crimes again.

"It's dishonest to have in sentencing something we couldn't accomplish," said Alvin J. Bronstein, director of the American Civil Liberties Union's National Prison Project.

A related casualty of the new law is parole -- a system devised partly in the belief that prisoners can be reformed before their sentences are completed. Under the new law, federal prisoners will be required to serve their full sentences.

Civil libertarians, judges and Justice Department attorneys agree that the new sentencing commission will have great power -- the power to decide who should go to prison and how long they will stay there.

But they are at odds on how long sentences should be. Attorney General Edwin Meese III -- a nonvoting member of the new sentencing commission -- says he favors keeping habitual criminals in prison for longer periods of time, but would consider shorter sentences in certain other cases. The ACLU generally favors much shorter sentences than those currently imposed.

"Prison space is a scarce resource," said the ACLU's Bronstein. "In many cases you can achieve more for society if you send 10 people away for three months than three people for three years. You'd have more people getting a harsh lesson" and fewer convicts becoming so hardened by the experience that they turn more violent.

The American Bar Association wants a commission that is "creative in suggesting punishments that are not limited to imprisonment," said Laurie Robinson, director of the ABA's criminal justice section. "A range of alternatives should be available for persons who commit less serious crimes."

All sides agree that the federal prison population will swell. Norman A. Carlson, director of the Bureau of Prisons, said the number of federal inmates -- which has increased 42 percent since 1981 -- is likely to grow more because of the new sentencing provision and, to a lesser extent, the law's creation of several new federal crimes.

"If they continue with the national trend started by sentencing commissions on the state level , we're going to have massive overcrowding in prisons with people locked away for longer and longer periods of time," said Bronstein.

The length of sentence for each federal crime -- and the determination of who will go to prison -- will depend, Senate aides say, on who is on the seven-member commission.

President Reagan is expected to receive the first list of nominees this week from the U.S. Judicial Conference, a panel of federal judges headed by U.S. Chief Justice Warren E. Burger.

The list will contain at least six names from which Reagan is expected to choose the three commission members who must be federal judges.

Then within the next few weeks, Reagan will receive a list from the Justice Department of names culled from more than 30 organizations representing prosecutors, defense attorneys, criminologists and crime victims, according to Deputy Associate Attorney General Jay B. Stephens. Reagan is expected to choose the remaining four members from the department's list.

Stephens said he did not know how many names the department would suggest, but that the list would depend in part on the backgrounds of the judges on the Judicial Conference's list.

"We want to come up with a commission that has a broad base of experience," Stephens said. But he added that the department would not base its decisions on narrow political considerations. Under law, no more than four of the seven members can belong to the same political party. The members must be confirmed by the Senate.

The commission is supposed to submit its guidelines to Congress for approval next year.

In the meantime, several problems have turned up, according to U.S. Appeals Court Judge Gerald Bard Tjoflat, chairman of the Judicial Conference's probation committee.

The legislation provides that only full-time federal court judges may serve on the commission. But senior judges, who are retired but continue to serve part time, presumably would have more time to devote to the commission.

In addition, commission membership is a full-time job under the law. Burger, in a Dec. 13 letter to President Reagan, complained that that requirement presents a "serious issue of constitutionality" and creates an additional burden on judges' caseloads.

Finally, no funds have been provided for the commission yet. However, legislation was introduced in the House this week that would allow retired judges to serve on the commission and authorize the panel to submit a budget.