By sending U.S. troops into northern Iraq - aided by British and French forces - to protect, feed and care for hundreds of thousands of suffering and dying Kurdish refugees, President Bush this week did an abrupt about-face from his previous position of trying to stay out of the situation.

This does not mean that his earlier stance was wrong. Indeed, the concerns about what such intervention might mean and where it could take the United States in the Middle East quagmire are just as valid as ever.But the pressures had grown so enormous for America to do something that Bush was forced to act. The desperate plight of perhaps 2 million Kurdish refugees who had fled into inhospitable mountains bordering Iran and Turkey without food, shelter or medicine was clawing at the conscience of the world.

Air drops of food were insufficient and Kurdish men, women and children were dying at the rate of 1,000 a day or more. And the Bush administration was being criticized on all sides for having urged the Kurdish uprising against Saddam Hussein, yet failing to help when the rebellion failed and Kurds fled for their lives.

Certainly, the president cannot be faulted on humanitarian grounds for responding and moving into northern Iraq. Something had to be done.

But let there be no ignoring the risks involved. By moving into northern Iraq with military forces and air power, the United States has put its foot in some quicksand. Consider the following factors:

- Helping the Kurds is not going to be like short-term disaster relief after an earthquake or natural disaster. If the Kurds refuse to go home because they fear for their lives - a not-unreasonable view given Saddam's murderous history - they may become internal exiles for years. At what point can the United States simply walk away?

- As part of helping the Kurds, it is necessary to move them from high mountains into warmer, lower-lying areas in northern Iraq, thus expanding the "protected" territory for the refugees.

- Iraq has protested this invasion of its territory but has indicated it will not interfere. The United States and its allies are too powerful in any case. But how will the allies keep Kurds from using their new secure base to launch attacks against nearby Iraqi troops? There is no way to have enough U.S. troops on hand to prevent hit-and-run raids by Kurdish guerrillas. What if Iraq tries to retaliate?

- How many U.S. soldiers will be enough to control the situation? "That will be up to the Kurds," Bush says. This seems to be leaving the depth of U.S. commitment in someone else's hands.

- The Kurdish enclave could become a semi-permanent occupied territory. The area has become a sort of instant West Bank. Like the Palestinians in the West Bank, the Kurds want independence or at least a significant degree of autonomy.

- If the stay by U.S., French and British troops in Iraq turns out to be lengthy, a significant restlessness is bound to occur among other Arab nations. One of Saddam's themes from the beginning of the Persian Gulf war - and effective in some quarters - was a warning that foreign troops were trying to occupy Arab lands.

The only hope of quickly resolving the situation, aside from the overthrow of Saddam - an event that Bush still would like to see - is to quickly make the Kurdish problem one for the United Nations.

But unlike the carefully crafted steps Bush took through the United Nations leading up to the war against Saddam, the move into northern Iraq was done without U.N. consultation.

Whether the president can succeed in dumping the whole situation into the lap of the U.N. is problematical, but he should push hard for such an alternative.