They already think Iraq has disobeyed a UN rule called resolution 1441 which orders the country to get rid of all its weapons.
However, convincing other countries like France and Germany that starting a war against Iraq is a good idea has been difficult.
They want to give weapons inspectors more time to search the country, in the hope that a peaceful solution to the problem can be found.
And even if France and Germany do finally agree that fighting has to start, they will ask the UN to make a new resolution before any military action begins.