President Rodrigo Duterte's decision to terminate the Visiting Forces Agreement was well studied and not based on a whim, Malacanang said on Monday.

Presidential Spokesperson Salvador Panelo also slammed former Foreign Affairs Secretary Albert del Rosario, saying he should stay retired after the latter advised Duterte to attend the US-ASEAN Summit in Las Vegas in March.

"I suggest he stays retired. The President knows what he is doing. He doesn’t need advice from those who have failed in their term as government officials, especially from the one who lost the West Philippine Sea to the Chinese government," he said in a press briefing.

During his stint as head of the Department of Foreign Affairs, Del Rosario initiated the filing of a petition against China's historic and sovereign claim in almost the entire South China Sea, including the Philippine-claimed West Philippine Sea, before the Hague-based UN Arbitral Tribunal.

But when Duterte assumed office and the decision by the tribunal came out in favor of the Philippines, the current administration decided to put it at the back burner and instead pursue a friendly stance with China, which continued with its aggressive activities in the South China Sea.

China did not recognize the arbitral ruling despite being a signatory also of the United Nations Convention on the Law of the Sea, which became one of the bases for the Permanent Court of Arbitration to favor the Philippines.

Duterte has decided to reject US President Donald Trump's invitation to the US-ASEAN Summit after Washington passed its 2020 Budget Law with a provision barring Philippine government officials from entering America for their alleged involvement in the human rights violations in the country as well as the continued detention of opposition Senator Leila de Lima.

Aside from barring US senators responsible for the passage of such law against Philippine officials from entering the country, Duterte recently ordered the revocation of the VFA after Washington canceled the visa of Senator Ronald dela Rosa.

Dela Rosa is Duterte's former chief of the Philippine National Police, which started implementing the war on drugs that claimed over 5,000 people already since it was launched in July 2016.

Contrary to the claim of some quarters that the decision to abrogate the VFA was only made on a whim, Panelo said it was not.

"It’s not, as expressed by some, a decision on a whim. It is a studied response to acts that the President deems to be not only an intrusion but an assault to the sovereignty of this country," he said.

"And to those who are thinking that this is a rash judgment, let me remind them that this President is a tactical and thinking president who has never lost an election, and who has thread a path that ordinary mortals, as well as even those pseudo-intellectuals have not thread," Panelo, also the chief presidential legal counsel, said.

"He has done controversial things but he remains to be on top of the surveys, whether it’s a trust rating, it’s a satisfaction rating or an approval rating. The Filipinos overwhelmingly support this President. Those of course who oppose constitute a measly six percent," he explained. Celerina Monte/DMS