MANILA (PHILIPPINE DAILY INQUIRER/ASIA NEWS NETWORK) - What is the extent of military and police support for Philippines President Rodrigo Duterte, almost three years into his controversy-filled presidency?

From the day he assumed office on June 30, 2016, Duterte has steamrollered his way from one controversy to another.

The controversies are intentionally generated by the president himself.

He has cursed God, blasphemed the Church, scorned priests, mocked women, badmouthed foreign powers, slurred critics, and threatened human rights advocates.

Duterte's most controversial policy and the centrepiece of his presidency is his bloody war on drugs.

It has so far seen 4,000 people killed by policemen, and 23,000 more by masked vigilantes suspected of being state agents.

Another controversial move by the Duterte administration is its complete reclassification of ally and enemy in our international relations.

He has assumed a posture of hostility toward the United States while grovelling to become a close ally of China.

This despite China's occupation of waters and shoals belonging to the Philippines in the West Philippine Sea.

Crucial to Duterte maintaining power in government is the backing of the police and military establishments.

So what has been the effect of these controversies - and several other scandals - on their support for the president?

The police force has always been reliably servile to whoever occupies the presidency.

Under Duterte, policemen have been the fawning enforcers of his brutal drug war.

The police will stick it out with whoever is president until the tide shifts in favour of a change in power.

The police force never creates that tide of change; it merely rides it to benefit from the resulting change.

It is the military establishment that has served as the fulcrum of power in Philippines history.

People power succeeds or fails when the military tilts its weight one way or the other.

We have seen this in the successful ouster of both Ferdinand Marcos and Joseph Estrada, and in the failed attempts to overthrow Gloria Arroyo.

The military has been enigmatic in its reaction to the many controversies surrounding the president.

But there's one controversy where it has clearly made known to Duterte that there are limits to his excesses.

When the president issued Proclamation No 572 voiding Senator Antonio Trillanes's amnesty, Duterte ordered the military to arrest the senator and commence court martialing him for his alleged complicity in a failed coup d'état in 2007.

In a clear act of defiance, the military refused to implement the presidential order.

Duterte has now been forced to go to court and apply for a warrant of arrest against Trillanes, his long-time political rival.

The rebuke stung the president.

He blasted the military's ingratitude, reminding them that he has doubled their salaries and given them new weapons.

He even challenged soldiers to stage a coup against his administration.

Whether the military "pushback" is due to self-interest (many top military officials are amnesty beneficiaries) or because soldiers sincerely feel that their "loyalty is to the constitution", it has been demonstrated to Duterte that his propensity to misuse power has limits.

Public discontent is rising because of the worsening economy.

Even the middle class is complaining of high prices.

Meanwhile there are unanswered questions on the president's health.

His pivot to China is not resulting in any kind of benefit for our country.

His approval rating is plummeting, emboldening opportunistic politicians to reinvent themselves as government critics when they see the tide turning.

All these developments will lower public tolerance for Duterte's self-inflicted controversies, making fertile ground for popular unrest.

If he refuses to heed the warning delivered by the Trillanes fiasco, President Duterte may end up giving the military an excuse to tilt the fulcrum of power away from his administration.

The writer is an Opinion columnist with the paper. The Philippine Daily Inquirer is a member of The Straits Times media partner Asia News Network, an alliance of 23 news media entities.