Registration gets underway in the Philippines on Tuesday for one of the world's biggest midterm elections, headlined by what could be a bitter proxy battle between President Ferdinand Marcos Jr. and fiery predecessor Rodrigo Duterte.

The May 2025 election will be a litmus test of Marcos' popularity and a chance for him to consolidate power and groom a successor, which the influential Duterte family has signaled it is determined to stop after an acrimonious falling-out.

Philippine presidents are limited to a single, six-year term.