What constitution did the short-lived "1st Philippine Republic of 1898 operate under?

The "1st Philippine Republic of 1898" operated under the Malolos Constitution, which was the first republican constitution in Asia. Adopted on January 20, 1899, this constitution established the Republic of the Philippines following the declaration of independence from Spanish rule. The Malolos Constitution emphasized democratic principles and laid out the structure of the government, detailing the branches of power, civil rights, and the role of the legislature, executive, and judiciary.

It is significant that the Malolos Constitution emerged during a crucial period in Philippine history, marked by a desire for self-governance and national identity. Despite the short-lived nature of the Republic, which lasted only until 1901 due to the subsequent Filipino-American War, the Malolos Constitution represented a pivotal step toward establishing a sovereign nation.

In contrast, the other options listed pertain to later developments in Philippine governance—the Constitution of 1935, the Commonwealth Constitution, and the 1973 Constitution are all foundational documents that governed the country during the American colonial period, the Commonwealth era, and the Martial Law period, respectively. Each of those constitutions followed the Malolos Constitution and reflected different political contexts and challenges faced by the Philippines.