When the Obama administration settles on its “AfPak— strategy — that is, Afghanistan and Pakistan — top priority has to go to Pakistan.

[IMGCAP(1)]It’s the most dangerous place on earth: nuclear-armed, menaced by terrorists, economically in crisis and mired in political turmoil.

Moreover, U.S. intelligence officials say, Pakistan is the likeliest source of terrorist attacks on the United States.

Protecting Afghanistan from Taliban advances is important — and U.S. troop commitments there will be a major domestic concern — but preventing chaos in Pakistan is vital to U.S. security.

It’s a daunting and complex goal that will require all the formidable diplomatic skills of the administration’s “AfPak— czar, Richard Holbrooke.

President Barack Obama has to play a personal role by declaring that the United States is decisively dedicated to securing democracy and fostering social and economic development in Pakistan.

Congress has to play its part by passing legislation sponsored by Sens. John Kerry (D-Mass.) and Dick Lugar (R-Ind.) providing $1.5 billion a year in economic aid over the next five years and promising renewal after that.

The United States has to convey to the Pakistani population that our country is not only interested in Pakistan’s role in the war on terrorism, but also will help it modernize its schools, health system and economy.

For more than 20 years, U.S. aid has been almost entirely military — and even that was not used to establish a counterinsurgency capability, but to buy conventional weaponry that Pakistan’s military wanted to counter India.

That’s changing, but so far Pakistan is losing the war against terrorism and the credibility of democratic government is also cratering.

The military failed to defeat Islamic extremists in the scenic Swat Valley, located less than 100 miles from the capital, Islamabad, and the government was forced into a deal allowing Islamists to impose Sharia, or Islamic law, in the region.

This was represented as a strategy to divide “moderate— Islamists from “extremists,— but it was widely seen as capitulation.

Swat is only one of several regions in the country where the government is losing out to insurgents, notably the misnamed Federally Administered Tribal Areas, a sanctuary for Taliban and al-Qaida fighters heading into Afghanistan.

Meantime, the country’s seven-month-old democratic government, headed by President Asif Ali Zardari, is rapidly losing public support, threatening the whole idea of democratic rule.

The latest and worst blow was the brazen March 3 terrorist attack on a motorcade carrying a visiting cricket team from Sri Lanka that killed six policemen and a driver in Lahore, capital of Punjab province.

Sri Lanka had been assured of “presidential style— security for the team’s visit. In fact, terrorists fired rocket-propelled grenades and AK-47s at the team’s bus and escaped with not a single attacker killed or captured.

Cricket is Pakistan’s national sport and the incident ensures that no international team will play there in the future.

Moreover, Zardari is being blamed for incompetence because he had recently replaced Punjab’s police commanders after rioting provoked by his arch-political rival, Nawaz Sharif, when the Supreme Court ruled that Sharif could not hold office because of prior criminal convictions.

In fact, Zardari opposed the ruling in court filings, but Sharif has accused him of plotting his ouster.

Sharif, who as prime minister in the 1990s dismantled courts that ruled against him, now is aligning himself with lawyers planning mass sit-ins and marches on Monday to restore a Supreme Court chief justice ousted by former President Pervez Musharraf.

Sharif, often identified as a “religious nationalist,— was a protégé of Islamist military dictator Zia Ul Haq. He accused former Prime Minister Benazir Bhutto of being a “Zionist-Hindu traitor— and, as prime minister, pushed a law to establish Sharia.

Zardari and Sharif’s fight is sapping faith that democratic politicians can rule successfully. Matters are made worse by high unemployment and inflation that’s worsened in the worldwide economic meltdown.

Zardari, husband of the assassinated Bhutto, has declared himself America’s ally in the war on terror and has permitted the CIA to use Pakistani territory to stage missile strikes on al-Qaida targets.

On the other hand, he has not been able or willing to crack down on extremist groups such as Lashkar-e-Taiba (LeT), which perpetrated last year’s attack on hotels in Mumbai, India, that killed 170 people, or Lashkar-e-Jhangvi, which bombed a hotel where New Zealand’s cricket team was housed.

Those groups originally were created by Pakistan’s military intelligence service, the ISI, to stage attacks in Indian-occupied Kashmir. They are widely believed to still have ISI connections.

Since Zardari’s election, some reforms have taken place in the ISI, but he clearly is afraid to confront it or the military openly, partly lest he seem to be doing so at the behest of the United States, which is increasingly unpopular in Pakistan.

Zardari, though a flawed leader, needs bolstering — especially by being able to show that alliance with the United States will produce tangible benefits for his people.

It may well cost a lot of money and effort to rescue the Pakistani economy, invest in education and infrastructure and persuade the army to concentrate on fighting terrorists instead of India.

It would also help if Holbrooke could engineer a détente with India to remove the army’s excuse for basing a majority of its troops on its eastern border.

But all this seems a reasonable investment — assuming the money is not squandered — in view of what it might forestall.

Pakistan’s population has never voted for Islamist parties, but it could succumb to a radical takeover out of exhaustion and disillusionment.

If we’re worried about Iran’s developing a nuclear weapon, contemplate Lashkar-e-Taiba in command of an entire arsenal.