WHEN CONGRESS returns next week, it will have an opportunity to restore funding for the Millennium Challenge Account. This innovative model for foreign assistance, launched by President Bush in 2002, is a welcome improvement on traditional aid programs: It sets easily understood eligibility criteria for poor countries hoping to receive aid, boosting the odds that the money will go to countries that use it well and creating an incentive for others to cut corruption, manage their economies responsibly and generally improve their policies in order to receive U.S. assistance. Mr. Bush has requested $2.5 billion for this initiative in 2005. But the House has set aside half of that, and the Senate has been even less generous.

Congress may feel that its development record is already good. On one count, federal spending on global anti-poverty programs rose from $6 billion in 2003 to $8 billion in 2004; it will rise to around $9 billion in the new fiscal year, even if the Millennium Challenge Account gets only half of what the administration has requested. But U.S. foreign assistance remains lower as a share of gross domestic product than that of any other rich nation, and others are expanding their donations faster than this country. Aid given by all the world's rich governments combined jumped from $52 billion to $68 billion between 2001 and 2003, reflecting the post-Sept. 11 preoccupation with failed states and a fresh determination to reduce poverty.

Congress may also think that the Millennium Challenge Account is not deserving of support because it has been slow to get off the ground. This slowness is less damning than it sounds: A new corporation to manage the account has been created from scratch, and administering aid is always a tough process. Once the corporation signs contracts with recipient nations, the grants will begin to flow. In the meantime, Congress needs to appropriate funds for the initiative in line with the amount promised at the time of its launch. Otherwise, the incentives to better policy in the poor world will not be credible.

Mr. Bush's initiative also faces challenges from within his administration. The transparent criteria used to identify poor countries with good policies have recently been muddied by a decision to include Georgia on the short list of 16 potential beneficiaries -- even though Georgia has failing grades in corruption, adherence to law and the share of its budget devoted to health and education, among other criteria. There may be sound political reasons to help Georgia's promising new government, but the help should not come from Millennium Challenge funds: The rationale for this account is that it is free of politics. To make his initiative succeed, President Bush must protect it not only from a tightfisted Congress but also from his own officials.