The intensified jockeying comes ahead of a national election on July 25. So far this year 248 politicians, including dozens of federal and provincial lawmakers, have changed sides - the most on record, according to the Free and Fair Election Network, an Islamabad-based watchdog. Of that 92 politicians have joined Khan's Pakistan Tehreek-e-Insaf, the second-largest opposition party and main rival of the Pakistan Muslim League-Nawaz, headed by former premier Nawaz Sharif.
Khan, whose anti-corruption campaign prompted the Supreme Court last year to disqualify and press criminal charges against Sharif, knows he needs to win over a large number of turncoat politicians. The key province is Punjab, which is Sharif's bastion.
"You need to have a critical mass of these defections, or several big-name defections, to have a real impact on the election," said Michael Kugelman, a senior associate for South Asia at the Woodrow Wilson Center in Washington.
If Khan is elected he will face a U.S. that remains distrustful of Pakistan's efforts to stamp out terrorism and continues to withhold billions of dollars in military aid. For Washington, a Khan victory would be an uneasy prospect. The 65-year-old is a staunch critic of the war in Afghanistan and U.S. drone strikes in Pakistan. He has also courted right-wing religious leaders, some with past links to the Afghan Taliban.
Still, policymakers in Washington "recognize that while a new civilian government might bring a different tone or some different policies, it is not likely to fundamentally change that orientation," said Joshua White, a former director for South Asian affairs at the U.S. National Security Council.
To investors, Khan represents an untested force in a country dominated by the dynasties of two parties -- Sharif's PML-N and the Pakistan Peoples Party headed by Bilawal Bhutto Zardari, the son of the assassinated former Prime Minister Benazir Bhutto.
"Investors were concerned over Khan's earlier statements about his plans to clampdown on corruption and withdraw all the agreements made so far," said Muzzammil Aslam, the chief executive officer at brokerage firm EFG Hermes Pakistan. "But Khan's 100-day plan eased off the investors' concerns as it didn't attack businesses."
In an interview with Bloomberg last year, Khan mocked the "musical chairs" politicians who chase power and money, but conceded he needed their numbers. Yet his success in drawing turncoats has fueled long-standing allegations from rival politicians and commentators that he's a pawn in the army's attempts to engineer a pliant government through media censorship and intimidation.
"The army, which has sparred with the PML-N for several years, has a strong interest in the next government not being led by the PML-N," said Kugelman.
Sharif has repeatedly insinuated he's a victim of a military plot as he faces a criminal trial after the Panama Paper leaks in 2016 showed his family used offshore companies to buy high-end London apartments.
And while Khan has denied that he has support from the military -- which has ruled the nation for much of its 71 years -- he's praised the army for its handling of domestic security.
Asad Umar, a senior politician in Khan's party who is pegged to become finance minister if they come to power, said the PML-N were fueling a conspiracy for political gain.
"That is the very sensible narrative from their point of view when you foresee a defeat coming," he said by phone from Islamabad. "No one ever has given me some substance on this."
One defector to Khan's party lambasted Sharif's comments as an attempt to weave a conspiracy that papers over the PML-N's faults.
Omar Ayub Khan, the grandson of former military dictator Ayub Khan and no relation to the former cricketer, denies he was pressured by the forces to leave Sharif's group. He said PML-N members were switching sides because of the party's botched attempt to change an Islamic oath that lawmakers take, which resulted in a three-week protest that snarled up the capital in November.
Up to March, Gallup Pakistan voting intentions data shows that Khan's party has increased its lead by 3 percent to 24 percent since 2017, which is still second place to the PML-N's 36 percent -- a 2 percent decline over the same period.
For Pakistan's most recent prime minister, Shahid Khaqan Abbasi -- a Sharif loyalist who handed over to a caretaker administration last month -- defections are just a well-established part of the nation's politics that won't damage his party's chances.
"Pakistani politics is about turncoats," Abbasi told Bloomberg. "We have seen all this before."
While defections and other pressures have left Sharif's party "incredibly vulnerable", its hold on Punjab and its shepherding of billions of dollars of Chinese-funded infrastructure projects means it's still in the game, said Kugelman.
"No matter what's being thrown at it, the PML-N still stands a fair chance of reelection," said Kugelman. Khan's PTI "remains a one-issue party fixated on corruption -- an issue that many Pakistanis don't view as a top concern."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)