If you are a dual resident taxpayer, you can still claim the benefits under an income tax treaty. A dual resident taxpayer is one who is a resident of both the United States and another country under each country's tax laws. The income tax treaty between the two countries must contain a provision that provides for resolution of conflicting claims of residence.
If you are treated as a resident of a foreign country under a tax treaty, you are treated as a nonresident alien in figuring your U.S. income tax. For purposes other than figuring your tax, you will be treated as a U.S. resident. For example, the rules discussed here do not affect your residency time periods.