PRESIDENT Rodrigo R. Duterte may still declare martial law, assume emergency powers or set up a revolutionary government as a last resort to solve the country’s worsening illegal drug problem, his spokesman said yesterday.

Mr. Duterte won’t hesitate to act if he cannot get Congress to change the 1987 Constitution to address issues that also include corruption, traffic congestion and terrorism, presidential spokesman Salvador S. Panelo told a briefing in Malacañang.

Mr. Duterte’s spokesman issued the explanation when asked what the president meant by alluding to a “last card” during a speech in Leyte province last Friday. “He can impose martial law, he can declare a revolutionary government, he can use other emergency powers,” Mr. Panelo said.

“Do not force me to declare war, because I have something else,’’ the president warned on Friday. “I have a card which I can throw anytime and you won’t like it. But at least it will give a sense of order.”

On Monday, Mr. Duterte reiterated his desire for a constitutional change, adding that the military has become more concerned about government corruption.

Mr. Duterte placed Mindanao under martial law in 2017 after extremists linked to Islamic State raided Marawi City in southern Philippines, leaving about 100 people dead and displacing thousands after clashes with the military.

Lawmakers extended the 60-day martial rule until the end of 2017 to help state troops end the siege that lasted about five months. Congress again extended martial law, as requested by Duterte, in the restive south until the end of this year to help quell terrorism.

Mr. Panelo said changing the Constitution would ensure foreign investors can come in without restrictions. Duterte also thinks getting emergency powers from Congress would let him solve traffic congestion on the main highway of EDSA, he said. — Arjay L. Balinbin