He participated in the 1948 Arab–Israeli War as an artillery officer in the Jordanian army's predecessor, the Arab Legion, but his vocal opposition to British influence in Jordan led to his virtual exile to Paris as military attaché in 1952.

Abu Nuwar spent much of his time in exile between Syria and Egypt organizing opposition to Hussein and the monarchy, all the while maintaining his innocence in the Zarqa incident.

In his memoirs, Abu Nuwar recalled that his teachers in al-Salt would tell him and his classmates that the "Arab Nation was colonized and fragmented and that it was on the shoulders of our generation to take responsibility for freedom and unity".

[1] Afterward, he received training in the British staff college of Camberly for two years before returning to Jordan, which was formed out of Transjordan and the West Bank as a result of the 1948 war.

[10] During his assignment in Paris, Abu Nuwar met King Talal's son and successor, Crown Prince Hussein, who frequently visited the city during weekend breaks from his training at the Sandhurst Military Academy.

[3] Abu Nuwar was keen to gain Hussein's favor and disseminate to him Arab nationalist ideas calling for an end to British influence in the Jordanian military.

[18] Hussein then promoted Abu Nuwar to major-colonel and appointed Major General Radi Annab to Glubb's former position as chief of staff of the Arab Legion,[19] which was concurrently renamed the Jordanian Armed Forces.

[21][22] However, Abu Nuwar's ascendancy as head of the army was resented by its veteran Bedouin units; he was generally regarded as a competent staff officer, but did not have experience as a commander.

[24] To counterbalance opposition to him within the army's ranks, Abu Nuwar established the Fourth Infantry Brigade, which mostly consisted of Palestinians, who he believed would form an integral part of his power base within the military.

[23] Abu Nuwar was a major opponent of Iraq's Hashemite rulers (relatives of Hussein) and that country's pro-British prime minister, Nuri al-Said.

Hussein declared a state of emergency and his opposition against the invasion and agreed to Egyptian chief of staff Abdel Hakim Amer's request for Jordanian military intervention.

[29] To that end, Hussein instructed Abu Nuwar to immediately launch Operation Beisan, which entailed a Jordanian-Syrian armored invasion of the Israeli coastal plain, which was seen as Israel's most vulnerable region due to the short length between the coast and the Jordanian-held West Bank.

[31] According to then-Public Works Minister Anwar al-Khatib's recollections, Abu Nuwar argued that his troops would quickly lose control of the Hebron and Nablus regions to Israel, but would "defend Jerusalem to the last man and the last drop of blood".

[34] During the Suez Crisis, Hussein requested that Syria, Saudi Arabia and Iraq send troops to Jordan as a precautionary measure to prevent a potential invasion of the country by the tripartite allies.

[39] Meanwhile, serious divisions emerged in the Jordanian state over reactions to the Eisenhower Doctrine,[40] which ostensibly aimed to stem Soviet expansion in the Middle East, but was viewed by Arab nationalists as a neo-colonialist ploy to control the region.

[37] Later, Nabulsi publicly declared his intention to establish relations with the USSR and pursue a political union with Egypt and Syria, and requested from Hussein a confirmation of his dismissal of several royalist officials.

[42] Amid the political chaos in Jordan and two days before Nabulsi's resignation, an army unit from the First Armoured Brigade commanded by Captain Nadhir Rashid engaged in a maneuver, named Operation Hashem in honor of the Hashemite royal family, at the major intersections of Amman.

[44] Abu Nuwar sought to allay Hussein's concerns and told him it was a routine exercise executed numerous times in the preceding years to monitor the traffic into and out of the city,[44][45] while Rashid later claimed it was part of a broader contingency plan to move troops to the West Bank in the event of an Israeli invasion.

[47] Pearson has said the "incident is steeped in mystery and persistent controversy",[47] and Anderson likewise has written that "questions abound about whether this coup attempt originated with the military, led by Abu Nuwar and the Free Officers, or with the king and the Americans, who wanted an excuse to remove" the Arab nationalist movement "from Jordan's political scene".

[48] The incident coincided with a delivery by Abu Nuwar of an ultimatum to Prime Minister Said al-Mufti (Nabulsi's successor) warning Hussein to appoint a government reflecting the will of the elected parliament or face an army revolt.

[48] Both accounts also agree that as Hussein made his way into Zarqa, he was cheered on by loyalist soldiers and he intervened in the middle of the clashes at his own risk and was emotionally embraced by his supporters,[47] who chanted "Death to Abu Nuwar and all the traitors!

By nightfall, Abu Nuwar persuaded Hussein to allow him to leave the country and on the morning of 14 March, he officially resigned and departed for Damascus, Syria with his family.

[50] Al-Hiyari claimed that prior to the incident at Zarqa and shortly after the forced resignation of al-Nabulsi's cabinet, palace officials had canvassed the army general staff to inquire about the officers' opinions regarding a change in direction of the new government away from the pan-Arabist policies of Egypt and Syria.

[50] Abu Nuwar consistently denied any betrayal of Hussein and claimed he was a "fall man", the victim of political intrigue in the kingdom in which his rivals sought to discredit him.

[55] In coordination with Abu Nuwar, the following day, a Patriotic Congress composed of Hussein's opposition was held in Nablus in the West Bank demanding major palace officials be dismissed, expulsion of the American ambassador and military attaché, rejection of the Eisenhower Doctrine, federal unity with Egypt and Syria and reinstatement of the dismissed army officers, including Abu Nuwar.

[55] As a result of the congress, Hussein put Nablus, East Jerusalem and Amman under military curfew, dissolved political parties, imposed press censorship, dismissed municipal councils in the West Bank in favor of military governors, disbanded Palestinian-dominated army units, arrested al-Nabulsi (who had since been made foreign minister) and dismissed the cabinet of Prime Minister Fakhri al-Khalidi.

[56][57] Although he eventually relaxed some of these measures, namely military curfews and severe press censorship, Hussein's moves significantly curtailed the constitutional democracy that existed in Jordan in the mid-1950s.

[56] The group attempted to recruit university students in Jordan to form the vanguard of the nationalist movement in the country, funded the smuggling of weapons to Palestinian dissidents in the West Bank and the refugee camps around Amman, financially assisted Jordanian officers and politicians dismissed by Hussein, and organized assassination attempts against leading royalist politicians, including al-Rifai, Talhouni and Hazza al-Majali.

[2] The following year,[61] or in 1965,[2] Abu Nuwar returned to Jordan after being pardoned by Hussein as part of a broader reconciliation with exiled dissidents in a bid to co-opt opposition to his rule.