THE UNITED STATES has reacted swiftly and generously to Haiti's calamity, both with a colossal charitable response from individuals, enterprises and organizations and with a substantial commitment of troops, money, medical help and high-level attention from the government. But the Obama administration can and should do more, and quickly, to ease the vast burden of relief and rebuilding and to channel cash to Haitian families in dire need. Specifically -- and at a minimum -- it could accomplish those goals by allowing Haitians with relatives in the United States to join their families here as quickly as practicable. Instead, it...