"This is dramatically lower than what our military leaders have consistently told us over the course of repeated visits to Iraq that they require, and that is needed to support Iraq in safeguarding the hard-won gains that our two nations have achieved at such great cost," the senators said in a statement. "We are very concerned by the prospect that a follow-on force might lack the capabilities and authorities necessary to help Iraqis ensure stability across the disputed territories in northern Iraq, which we consider an essential mission."