That previous parliament, elected in 2009, was dissolved by the emir of Kuwait in December 2011. But the dissolution was deemed illegal in Wednesday's ruling, meaning that the new officials, elected in February, must now hand back their mandates.
The previous parliament regains its constitutional powers as if it had not been dissolved, said the court's verdict, according to Agence France-Presse.
Kuwait has what is arguably the most modern and open political system in the Arabian Peninsula. Its 50-member Parliament is directly elected, and officials are free to criticize the dynastically appointed emir and his ruling family.
But the emir still wields power over these elected officials, as evinced by the fact that Sheikh Sabah Al Ahmed Al Jaber Al Sabah, the emir since 2006, has dissolved parliament on four separate occasions.
Although Wednesday's court decision essentially repeals the emir's last dissolution, it will work in his favor by temporarily protecting the Al Sabah dynasty.
Lead-up to a Showdown
Divisions between an increasingly Islamist parliament and the Western-allied ruling family have worsened in recent years, and February's elections had installed the most hostile legislature yet. Two-thirds of the seats were filled by opposition leaders, who then vowed to expose corruption at the highest levels. Two dynasty-allied ministers have since resigned in the face of parliamentary scrutiny.
Wednesday's ruling prevented another possible ouster, as Interior Minister Sheikh Ahmad Al Humoud Al Sabah had been next in line for an investigation by the opposition.
Even before this new parliament took office, public dissatisfaction was apparent. Last year, then-Prime Minister Sheikh Nasser Mohammad Al Ahmad Al Sabah, the emir's nephew, was ousted by opposition-led corruption charges, which were preceded by public demonstrations against his rule.
This month, the emir was hesitant to call for another parliamentary dissolution -- such a move would lead to new elections that would almost certainly have installed an even more hostile legislature. By reinstating the pre-2012 parliament, which was confrontational but still led by a pro-monarchy coalition, the court has sidestepped that problem.
Still, the decision may backfire as it is sure to provoke the anger of Kuwaiti citizens.
Against the backdrop of the Arab Spring sweeping the Middle East, this is a worrisome development for Kuwait. It is on the uppermost edge of the Arabian Peninsula, a region whose West-friendly governments are growing uneasy due to simmering unrest.
The past year has already seen a popular uprising in tiny Bahrain, as well as a violent conflict in Yemen between the U.S.-backed government there and Al-Qaeda terrorist groups. The other peninsular countries -- Saudi Arabia, Qatar, the United Arab Emirates and Oman -- remain relatively stable, though conflicts everywhere are bubbling beneath the surface and sometimes erupting into small-scale protests.
In Kuwait, religious divisions also threaten to exacerbate political turmoil. The ruling dynasty is Sunni Muslim, but Shia Muslims make up about one-third of the population. In the middle of the tumultuous Arab Spring, especially with the Shia-led protests in nearby Bahrain, Sunni leaders in Kuwait are wary of unrest within their borders.
Further complicating matters are foreign interests. The United States has a real stake in Kuwait's stability since it has 15,000 troops stationed there currently, according to a recent report from the Associated Press. Washington sees this as a key bulwark against Iran and any continuing insurgencies in Iraq. Without the Al Sabah family in power, that troop presence would likely be more difficult for the U.S. to maintain.
Add in the political turmoil likely to be caused by Wednesday's decision, and Kuwait is in danger of reaching a tipping point.
On Wednesday, political analyst Anwar al-Rasheed told AFP that calling for new elections would be the best way to ease friction in the oil-rich Gulf state. Until then, the situation will likely remain tense.
This historical ruling will certainly lead to intensifying the political crisis in the country that has been suffering for a long time, he said.