House Democrats sent out two clear messages last week: they intend to put the Korean and other scandals behind them, and the era of reforming the seniority system is over.

Seniority system reform may have died a natural death. The energies and ambitions of newer members are no longer bottled up underneath the tyrannical rule of all-powerful committee chairmen. Nor is legislation. Power has been distributed to the point that reformers are now looking for a way to estrain the legislation pouring out of the some 150 House subcommittees, the beneficiaries of the distribution-of-power process.

But the ethics reform movement is a different case.It was throttled before anybody got badly hurt. Last week's Democraic caucus was in a "circle the wagons" mood, rallying around to protect two members -- Charles H. Wilson and Edward R. Roybal, both California Democrats -- reprimanded in the Korea scandals from losing their subcommittees There also was an indication that many members felt their troubles with the scandals could be blamed on the press.

"Ethics" has always been an Achilles' heel for Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.). When he was clected speaker in 1976, with the Korean influence-buying scandals swirling around the House, he moved quickly to put through a tough, new ethics code.

That was wise politics as well as self-protection. Newer members, elected as reformers in 1974 in the wake of Watergate, were demanding a move that would allow them to show they were not part of the Korea mess. And because Korean businessman Tongsun Park had given O'Neill two dinner parties and several gifts, the speaker had to put some distance between himself and the scandals.

But at the at issue in 1976 was whether Rep. Robert L. F. Sikes (D-Fla.) should be stripped of his subcommittee chairmanship after he was reprimanded by the House for profiting in a conflict-of-interest deal. O'Neill supported Sikes' bid for reelection for subcommittee chairman, a move that got him in trouble with some newer members. Sikes was deposed anyway.

This year O'Neill felt condident about what the membership wanted. He had felt the impact of grumbling by House members about the part of his ethics code that limited outside earned income. And he knew that many members believed the Korea scandals had been overblown by the press.

So the leadership led to move that clearly signaled it favored letting Roybal and Wilson keep their subcommittees: it closed the caucus to public and press while members debated motions to require a caucus vote on whether to let reprimanded members remain as subcommittee chairmen. The move lst.

O'Neill avoided the press that day, but Majority Leader Jim Wright (D-Tex.) justified closing the caucus on the ground that members could be trusted to do what was right in secret. "Members elected by the public are doing the public's business. I'm not aware anyone elected you," Wright snapped at reporters. O'Neill told the caucus it had a right to discuss party matters in private.

It was a theme echoed by even those with a reputation as among the most "reform-minded" Democrats -- Morris K. Udall (Ariz.), Fortney H. (Pete) Stark (Calif.), Richard L. Ottinger (N.Y.), Abner J. Mikva (Ill.) and Phillip Burton (Calif.).

They were discussing the reputation of their colleagues and that should be done in private, so as not to "smear" them, they argued. But Rep. Richard Bolling (D-m/o.) pointed out that that argument was "incomprehensible," since just two months ago the same two members had the charges against them of accepting money from Park and failing to report it read and debated in public when they were reprimanded by the House. Only procedural changes were being discussed last week.

But in closed session, the Democrats voted 161 to 73 not to require caucus votes on the subcommittee chairmanships of Roybal and Wilson. They also voted not to make convicted or indicted chairmen stand aside.

The action was important because it signaled that, while a tough new ethics code may be on the books, there isn't going to be much in the way of punishment for violating it.

That is significant departure from the reform mood of a few years ago. Then, reformers were demanding that chairmen such as Wright Patman, F. Edward Hebert and W. R. Poage be ousted, not because they violated an ethics code, but because they were autocratic and out of the Democratic mainstream.

Reformers argued then that chairing a committee was a "privilege" and that chairmen must be accountable to the Democratic caucus for their behavior.

Last week, the caucus indicated it does not want that responsibility.

Next month, the caucus must decide whether Rep. Daniel J. Flood (D-Pa.), chairman of the Labor-HEW appropriations subcommittee, should be allowed to keep his post while under indictment for bribery and other charges.

Up until a month ago, oddsmakers were almost certain that Flood would lose his seat. They are no longer so sure.