Under the Insular Cases of 1901, the Supreme Court ruled that unincorporated territories and insular possessions of the United States, which were not on a path toward statehood, had limited applicability of the U.S. Constitution. At the time, these included Guam, the Philippines, and Puerto Rico, acquired in 1898 at the end of the Spanish–American War. According to the decision, those born in insular possessions or unincorporated territories were not eligible for citizenship, though they were considered nationals and could hold a U.S. passport and gain diplomatic protection from the United States. Passage of the Expatriation Act of 1907 eliminated the uncertainty created in 1855, definitively stating that marriage solely determined all women's nationality. The law immediately revoked the nationality of married women, regardless of whether they were born in the United States or naturalized, if they were married to a non-citizen. It was retroactive and did not require a wife's consent, leaving many women unaware that they had lost their nationality.