WHERE THE CANDIDATES STAND ON CRIME AND ETHICS. The Reagan administration, although tough on law and order, has been tainted by `sleaze.' These issues have been central in the '88 campaign. Sixth in a series on the challenges the next president will face. DUKAKIS

ON April 14, the Supreme Judicial Court in Massachusetts ruled that state police had the right to set up roadblocks and checkpoints to catch drunken drivers. The decision was a victory for Gov. Michael Dukakis, who had pushed through the legislation. It was a defeat for the American Civil Liberties Union (ACLU), which had challenged the law. But in light of Mr. Dukakis's lagging bid for the presidency, it is perhaps more important as a symbol of his frustration in conveying his record and his message on the rule of law.

George Bush says the governor is soft on crime. The images are powerful. A couple is assaulted by a convicted murderer who was allowed out of a Massachusetts prison on a weekend furlough. Boston policemen endorse Vice-President Bush over their own state leader. Dukakis is a self-avowed ``card-carrying member of the ACLU'' (words spoken by the governor when, ironically, he was defending his tough roadblock law against an ACLU challenge). And a high-level Massachusetts official appointed by Dukakis is in jail for defrauding the state.

But Dukakis's record reveals a much tougher attitude toward crime and government ethics than such symbols suggest.

Crime. ``We're more than a little frustrated'' with the soft-on-crime characterization, says Patrick Hamilton, who headed the governor's Anti-Crime Council before joining the Dukakis campaign.

As evidence of his hard-line stance on crime, Dukakis cites statistics and programs. For example, the per capita homicide rate in Massachusetts is less than half the national average. Under Dukakis, the serious-crime rate has dropped 13 percent in five years, vs. a 4 percent increase for the nation.

Dukakis supporters credit the governor's programs, many of which he says he would adopt as president. He has increased the number of state police by 36 percent and initiated a drive to double the state and county jail space by 1993. He has stiffened penalties for drunk driving.

He chairs a monthly meeting of an anticrime advisory group made up of law-enforcement officials, legislators, and crime victims. As president, he would create a similar national council, he says.

And contrary to the claims of Bush supporters, Dukakis does not oppose mandatory sentences for people convicted of various crimes. This year he supported a law requiring judges to impose a minimum sentence for various crimes. Aides say that if the Supreme Court strikes down the national sentencing guidelines drawn up by the Reagan administration, Dukakis, as president, would support new, constitutional sentencing guidelines.

Ethics. Although there have been a couple of bad apples in the Dukakis administration, the governor is considered squeaky clean.

As president, he would apply the independent counsel (special prosecutor) law to Congress. He also supports curbing former members of Congress from lobbying their former colleagues after they leave office. And Dukakis has gone much further than his opponent when it comes to White House officials: He would restrict the top 800 people in the executive branch from lobbying their former agency for the duration of the administration.

Judges. The sleeper issue of the campaign may be the judiciary. The next president may appoint four Supreme Court justices and up to 200 federal judges, whose legacy would be felt into the next century.

Legal scholars give Dukakis high marks for his choice of judges, although they tend to lean toward the liberal and activist side. Aides say he has appointed both Republicans and Democrats to the bench - though they can't point to more than a couple of Republicans.

They also say he doesn't choose judges on the basis of ideology, since the screening process queries candidates about their past experience but not their views on issues. He would likely use a similar screening process for federal judges, aides say.