The party was formed from a split in the Syrian Communist Party, beginning in the late 1960s with disagreements over Arab nationalism and the authoritarian leadership of Khaled Bakdash. Radicals around Riyad al-Turk criticized Bakdash and asked for internal party democracy, as well as a more favorable view towards Arab nationalism and pan-Arabism. They later objected to the Bakdash leadership's decision to join the pro-government National Progressive Front in 1972. Essentially the choice facing the Communists then was to submit to the leadership of the Ba'th Party in the NPF, which brought a variety of restrictions, or attempt to function outside the law. The old leadership of the party under Bakdash chose the former option; the more left-wing elements followed Riad al-Turk into opposition, finalizing the split in the party. Turk's faction took the name SCP, but was also known by the name of its leader, as SCP.
In opposition
The party was able to operate reasonably effectively at first, although it was never very large, and for some time it negotiated over conditions of joining the NPF. However, Syria's intervention on the side of the Maronite militias and the Lebanese government against Arab nationalist and leftist Lebanese and Palestinian rebels, caused a firm break in relations. The SCP publicly and strongly condemned the intervention, provoking a crackdown from the government of Hafez al-Assad. The party then engaged in active opposition to the government, and in 1979 participated in the creation of the NationalDemocratic Rally, with four other leftist and nationalist opposition parties; it also, while itself renouncing violence, advocated dialogue with the Muslim Brotherhood and other SunniIslamists, who would engage in an armed uprising against the government few years later. This led to a harsh campaign of political repression, culminating in 1980 with the arrest of al-Turk and numerous other party members. Turk was not released until 1998, and became known as one of Syria's most prominent prisoners-of-conscience.
The party benefitted from the decreased political repression of the last two years of Hafiz al-Asad's rule and after his death, its members were very active in the Damascus Spring, a brief period of intense political and social debate that flourished in the second half of 2000 and in 2001. Riyad al-Turk was arrested as the government stamped out most of this activity in the autumn of 2001, when he outraged the government's sensibilities by remarking on television that "the dictator has died", in reference to Hafiz al-Asad. He was imprisoned, but later released following international pressure. In 2005, the party held a clandestine conference at which it adopted new rules and changed its name to the Syrian Democratic People's Party, signalling its adoption of western-style social democracy as its ideology, rather than its previous Soviet-style Marxism-Leninism; since the early 1980s, it had been highly focused on democracy issues, and the 2005 conference essentially formalized a development long in being. Party leader Faeq al-Mir was arrested in December 2006 after being taped by Syrian intelligence agents calling Lebanese politician Elias Atallah to offer condolences for the death of Pierre Gemayel, Lebanon's Minister of Industry. Al-Mir was charged with "undertaking acts that weaken national sentiment during times of conflict" and "communicating with a foreign country to incite it to initiate aggression against Syria or to provide it with the means to do so" and sentenced to three years in prison. Amnesty International adopted him as a prisoner of conscience and campaigned for his release.