To finish IRA violence

Americans have received a stark reminder of the extent to which some of their number are underwriting tragedy. They have been told that, without their support , it is very doubtful the outlawed Irish Republican Army could continue its violent tactics to get Britain out of Northern Ireland.

In this case the messenger was Britain's chief official for Northern Irish affairs, James Prior, starting a United States speaking tour. But, since many of the US contributors to the IRA have roots in the Irish Republic, they should also know that just this month Prime Minister Haughey made a renewed appeal against violence. And Mr. Haughey has earlier said he had conclusive evidence of support for the campaign of violence by Noraid (Irish Northern Aid), the same New York-based group that Mr. Prior called the IRA's main US provider of guns and money.

Such charges from such sources - not to mention from US officials - cannot be overlooked by any potential contributor to an organization that regularly denies them and claims humanitarian purposes. Whether violence is subsidized through intent or ignorance, the results are tragically the same.

Thus to Mr. Prior's reminder this week should be added what Mr. Haughey said as head of his country's government before elections now scheduled for next week. He condemned the Sinn Fein party's requirement that its candidates be ''unambivalent in support of the armed struggle.'' He said, ''The failings and deficiencies of the political system within Northern Ireland can only be corrected by lawful political means. . . .''

Mr. Haughey pledged that the Irish Republic would not be allowed to become a ''launching pad'' for violence in Northern Ireland. How cruelly ironic for the United States across the sea to become one instead.