The United States' decision to suspend security assistance to Pakistan has dealt a heavy blow to the already deteriorating relationship between Washington and Islamabad. It will also cast a shadow on US efforts to combat terrorism in Afghanistan, as Pakistan plays a pivotal role in the anti-terrorism campaign in the region.

Earlier this month, US President Donald Trump tweeted: "The United States has foolishly given Pakistan more than 33 billion dollars in aid over the last 15 years, and they have given us nothing but lies& deceit, thinking of our leaders as fools."

Days after this controversial tweet, US Ambassador to the United Nations Nikki Haley announced that Washington will withhold $255 million in assistance to Pakistan. Media reports suggest the US decision risks the suspension of $2 billion in aid to Pakistan.

In response, Pakistan suspended its defense and intelligence cooperation with the US amid rising domestic protests against Washington's "betrayal". The latest US action has plunged US-Pakistani ties to its lowest ebb as the military alliance between the two sides, forged after the Sept 11, 2001, terrorist attacks on the US, has practically ceased to function.

After 9/11, Pakistan severed its ties with the Taliban and joined the US in the fight against terrorism. Pakistani cooperation enabled the US to topple the Taliban regime in Afghanistan, and also helped restore the military alliance between Washington and Islamabad.

However, the US' military alliance with Pakistan has never been plain sailing. While the US suspected Pakistan's commitment and sincerity in fighting the Taliban, Islamabad was unhappy with the US drone attacks in Pakistan on targets the US claimed were used by terrorists to launch cross-border attacks in Afghanistan. Pakistan deemed the attacks on its territory as a violation of its sovereignty.

The truth is that Washington has never treated Islamabad as an equal and respected ally despite Islamabad hunting down hundreds of terrorists with the limited resources at its disposal and paying a heavy price for aligning with the US. Its intelligence sharing has also helped the US troops to hunt down the top leaders of terrorist groups, including Osama bin Laden.

Even though Trump's predecessor Barack Obama decided to end the Afghanistan war in 2014 and withdraw most of the US combat troops from the country claiming the situation there had "improved", the security outlook in both Afghanistan and Pakistan has remained as bleak as ever. And with the reconciliation process in Afghanistan being full of twists and turns, Pakistan has continued to suffer frequent terrorist attacks.

Under such circumstances, the suspension of US security assistance to Pakistan could be interpreted as a waning of Washington's commitment to fight terrorism in the region. This might be in line with Trump's "America First" doctrine, but it could reinforce the widespread perception that the US is not acting like a responsible power in the region.

The US has the responsibility to clean up the mess it has created in Afghanistan. It should also help Pakistan contain its homegrown terrorists and those that have infiltrated the country from Afghanistan. For both missions, Washington needs strategic support from Islamabad as Pakistan's border with Afghanistan is a pivotal passageway and supply line for US troops still stationed in Afghanistan.

Unless the US is prepared to wage a lone battle against the remaining terrorists in Afghanistan and find other ways to support its troops there who rely on supplies through Pakistan, dissolving a military alliance with Pakistan built over the years is not a good bargain for the Trump administration.

From a geopolitical perspective, given the icy US-Pakistani ties, Islamabad will be forced to further deepen strategic relations with Beijing and Moscow, a scenario which Washington may not want to see. An estrangement, let alone a divorce, is thus not the best option for the US and Pakistan.

The author is a senior writer with China Daily. wanghui@chinadaily.com.cn