By NBC's Amna Nawaz in New York, and Fakhar Rehman in Islamabad

Since assuming the presidency in Pakistan three years ago, Asif Ali Zardari has been hit with allegations of poor governance and corruption, watched his coalition government fall apart and has even seen his health falter. But this latest challenge, in the form of a Supreme Court inquiry into a political scandal dubbed "Memogate" by Pakistan's media, is testing Zardari's hold on power and has put his civilian government squarely at odds with the military establishment once again.

The court's investigation is centered on what -- if anything -- Zardari knew about a secret memo passed to U.S. officials after the May raid on Osama bin Laden's compound. The memo's existence was revealed by American-born, Pakistan-origin businessman Mansoor Ijaz in an October piece in The Financial Times. The eventually leaked contents of the memo -- requesting U.S. help to rein in Pakistan's military and intelligence in exchange for heavy American influence over national security deicsion in Pakistan -- "infuriated many in the armed forces," according to a senior military officer. "It will have a significant bearing on the political scenario if proven true."

The scandal has already forced the resignation of one senior Pakistani official -- then-ambassador to Washington, Hussain Haqqani -- who had played a crucial role in steadying the turbulent relations between America and Pakistan over the last few years, and now threatens to further destabilize Zardari's already-weak government.

Pakistan's military and its civilian government have a history of deep-seated tensions -- which occasionally boil over into full-blown coups -- dating back to the 1950s, when political parties began their struggle for supremacy in the early days of the country's independence. Zardari has himself felt the ire of the all-powerful army, once for attempting to bring the military's intelligence agency -- the ISI -- under civilian control, and again for pledging to dispatch the ISI chief to India after the November 2008 Mumbai attacks. Both times, his efforts were thwarted by the military. The government's distrust for the military and the military's disdain for the government provide the backdrop for every national crisis, of which there have been many this year alone.

Getting to the bottom of the Memogate scandal will not be easy. The case is already clouded with political motivation (it first brought to the Supreme Court by the leader of an opposition party, bent on dislodging Zardari from power), and every word of submitted testimony is first being parsed by the Pakistani press, then pieced together into wild speculation about legal conclusions.

• Pakistan's 'Memogate' triggers U.S. ambassador's resignation

Legal experts in Pakistan have offered a range of possible outcomes -- including Zardari being forced to resign, or being tried for treason, or his entire government collapsing. And while there is no firm timeline for proceedings beyond the first hearing on Monday, there is already, in much of the reporting, an assumption that such a memo could not have been drafted without the involvement of Zardari.

Despite a visit from Army Chief Gen. Ashfaq Parvez Kayani to Prime Minister Yousuf Raza Gilani's house today, after which a statement was released urging that military testimony in the case "not be misconstrued as a standoff between the Army and the government," the depositions given by Kayani and ISI chief Gen. Ahmed Shuja Pasha this week are certainly not helping the government's case.

Pasha, who met with Pakistani-American businessman and "Memogate" scandal-blower Mansoor Ijaz in London to review relevant evidence, testified that he believed the memo to be genuine and that Haqqani was involved. Kayani said in his testimony that the memo had already had "an impact on the national security," that there was "nothing denying the fact that the memo exists," and called for a swift and thorough investigation. Both statements, firmly stating that the memo exists, and that this issue needs to be looked into, fly in the face of previous government statements, denying the existence of the memo and dismissing the calls for inquiries as politically motivated.

• US halts $700 million in aid to Pakistan

U.S. Gen. Jim Jones, former national security adviser who acted as American conduit for the now-infamous memo, today submitted testimony that seemed to throw the government a lifeline, saying he had no reason to believe former Ambassador Haqqani was involved and that he did not believe the document to be credible.

Ijaz, the businessman at the heart of this controversy, also submitted testimony. The crucial deposition from President Zardari, however, has yet to surface. Zardari remains under doctor's care in Dubai, recovering from heart-related illness that forced a quick departure from Islamabad last week. He was scheduled to testify yesterday, and there is no word yet on when he will submit his side of the story.