Whether you agree with them or not, you have to admire the stamina of members of the Arlington Coalition on Transportation. For two decades, they have been arguing, demonstrating, petitioning, testifying and suing to stop the construction of I-66.

Last Sunday they were out in force again. Some three or four hundred of them, joined by several public officials, walked along several miles of the highway's right-of-way. Their purpose was to call President Carter's attention to this project in hopes of persuading him to put at least a moratorium on construction until current litigation is concluded. Their argument - an old and good one - is that trees should not be cut and a right-of-way cleared until it is absolutely certain that the highway will be built. Their belief that I-66 can still be stopped rests on yet another court case and on the hope that the compromise reached last winter between the Department of Transportation and Gov. Mills Godwin will come unglued.

A decade ago, we were among those who thought this highway would be built eventually whether or not it was needed because of the adamant view of the Virginia Department of Highways and the highway lobby. Last winter, after Gov. Godwin held funds for Metro hostage until he got agreement on I-66, we thought the matter was finally settled. Now, we are not so sure.

Come January, there will be a new governor and a somewhat different legislature in Richmond. A full review then of I-66 might poduce a different result from that reached last winter. If it does - and I-66 is never built - the credit will have to go to the Arlington Coalition on Transportation. Its members simply never give up.