我看可以。因為按照美國土安全部的明文規定：

U.S. citizens entering the United States at sea or land ports of entry are required to have documents that comply with the Western Hemisphere Travel Initiative (WHTI), most commonly a U.S. passport, a passport card, a trusted traveler card such as NEXUS, SENTRI or FAST, or an enhanced driver's license。而WHTI要求的旅行證件隻要能夠證明國籍身份即可：The Western Hemisphere Travel Initiative (WHTI) requires U.S. and Canadian travelers to present a passport or other document that denotes identity and citizenship when entering the U.S. It is a result of the Intelligence Reform and Terrorism Prevention Act of 2004 (IRTPA).不過還是建議你給小孩子辦個護照，我的小兒9個月大時就辦了護照。