It was unfortunate that President Reagan chose to veto - as he recently did - a modest legislative proposal designed to put young people to work on conservation projects in federal, state, and Indian lands. Congress should reenact the legislation next year.
The proposal would have established a new American Conservation Corps patterned - in theory if not structure - along the lines of the old CCC, the Civilian Conservation Corps of the 1930s.
In vetoing the jobs-conservation measure, Mr. Reagan said it would have merely created ''temporary make-work'' - in short, what he perceives to be a ''discredited approach to youth unemployment.''
Proponents, however, had been careful to put together a plan that was both modest in cost and specifically directed - namely, geared to environmental work. The measure, which cleared the Republican-led Senate as well as the more liberal Democratic House, would have cost $225 million over three years. That is hardly an enormous expenditure, considering a Pentagon weapons system can run upwards of $20 billion to $30 billion or more.
The new measure would have reached minority and economically disadvantaged youths. Youth unemployment remains a considerable challenge in the United States. Indeed, the type of emotional outburst seen in Detroit last week just before Halloween - when a number of young people set some 300 fires around the city - underscores the frustrations that can come to the surface when the future seems to be devoid of any hope or change. Noting that is not to condone such violence. Detroit officials should identify perpetrators of arson - and hold them accountable for their misdeeds. But surely, the type of irresponsible action represented by the Detroit fires is one reason a modest proposal such as the American Conservation Corps - with its emphasis on work and discipline - makes sense.