THE impulse to blast President Bush for his emphasis on overseas matters has zeroed in on its easiest target - foreign aid. Aid is a sitting duck any time for politicians playing to Americans' tendency to be most concerned about pocket-book issues at home. With an economy stuck out of gear and a presidential race bearing down, it's irresistible.It is heartening, therefore, that Congress has moved to revive, at least partially, a Soviet aid proposal it recently shot down. The original plan, put forward by two of Congress's most powerful Democrats - Sen. Sam Nunn of Georgia and Rep. Les Aspin of Wisconsin - would have set aside $1 billion from the defense spending bill. The funds would have gone both for emergency food relief and to help the Soviet military follow through on the destruction of thousands of its nuclear weapons. The new version would give the administration the option of using up to $500 million specifically for the destruction of weapons. Nunn and Aspin have argued, persuasively, that this is a sound investment in the security of the United States and its allies. But that rationale was nearly drowned out by the now-popular campaign slogan, "It's time to take care of our own." No one can deny that neglected problems in the US must be addressed. The president should concentrate more effort on economic recovery - beyond his capital gains tax-cut mantra. But "taking care of our own" shouldn't be given an isolationist spin. Americans seemed to feel good about themselves last January as their soldiers crushed the Iraqis. They should feel just as good when US dollars and expertise help establish the peace in Cambodia, help improve agriculture in parts of Africa, help the Andean nations fight drug production, or help Russians piece together a functioning, less militaristic, society. These and dozens of other aid projects are the preventive side of peacekeeping. They serve both the interests of those being helped and the interests of the US in a more peaceful, more prosperous world. And aid, it should be remembered, is only a tiny fraction of the federal budget.