Islamabad, Pakistan (CNN) -- Pakistan's Supreme Court has summoned Prime Minister Yousuf Raza Gilani to appear February 13 to be charged with contempt of court, his lawyer said Thursday.
The move raises the stakes in a long-running battle over the court's demand that the prime minister investigate President Asif Ali Zardari, among others, for suspected corruption.
Gilani has refused, saying the head of state is immune from prosecution.
If he is found guilty of contempt, Gilani could be forced from office, but his lawyer Aitzaz Ahsan said Thursday that Gilani would keep his position unless electoral officials disqualified him.
Ahsan said he was advising the prime minister to appeal the Supreme Court's decision to charge him.
"I have concerns about the tension between the institutions," Ahsan told reporters.
Seven of the Supreme Court's judges are currently handling the prime minister's case. If he appeals, the chief justice can assemble a larger panel of Supreme Court judges to consider the motion.
The contempt charges could be the beginning of the end for Gilani, said Ahmed Bilal Mehboob, the head of Pakistan's Institute for Legislative Development and Transparency, a think thank.
"Once he's convicted he will stand to be disqualified to be a member of Parliament and therefore disqualified from being prime minister," Mehbook said. "The speaker of the National Assembly can drag the process (out) but I don't think the Supreme Court will allow that to happen."
He welcomed the court move as a "good step towards the application of the rule of law.
"Far too many people get away with evading the rule of law" in Pakistan, he said. "This sends a message that no matter how powerful you are, you are not beyond the reach of the law."
Gilani will get a chance to defend himself in court, Mehboob said, but it is too late for him to stop the process by apologizing.
"That stage has passed," he said. "He could have done that when he was (first) summoned but he didn't."
Gilani told CNN last month that he would go to prison if necessary.
"If the court so desires, I have no objection," he said.
Gilani appeared in court over the contempt charge on January 19 in response to an order from judges to explain why he refuses to reopen lingering cases against President Zardari and others.
"We have the height of respect for the judiciary, but there is full immunity for the president -- not only in Pakistan, but in the entire world, too," Gilani said at the time.
Gilani's appearance last month came after weeks of political turbulence in Pakistan that have strained relations between the country's civilian and military leaders and fueled speculation about the possibility of a military coup.
The corruption cases stem from money-laundering charges against Zardari and his late wife, the former Prime Minister Benazir Bhutto. A Swiss court convicted them in absentia in 2003 of laundering millions of dollars.
After a controversial amnesty was granted in 2007 by then-President Pervez Musharraf to Zardari, Bhutto and thousands of other politicians and bureaucrats, the Pakistani government asked Swiss authorities to drop the case.
In 2009, the Pakistani Supreme Court ruled the amnesty was unconstitutional and called on the government to take steps to have the cases reopened.
The government has not done so, and the court apparently lost patience.
Since Gilani is the head of the government, the court justices view him as responsible and want him to explain why the government has not followed the court's order.
Gilani's argument that Zardari is exempt from prosecution did not appear to satisfy the judges.
"If the court concludes that he's in contempt, then they can take action against him," said Saeed-uz-Zaman Siddiqui, a former chief justice of Pakistan. "The maximum sentence is six months in prison."
Even if he went to prison, Gilani would not necessarily lose his premiership.
Pakistani law says that after a contempt of court conviction, the court sends a notice to the speaker of the National Assembly, the lower house of Parliament.
The speaker has 30 days to forward the notice to the Election Board, which has 90 days to decide if Gilani is disqualified as a member of Parliament and therefore disqualified as prime minister.
Ahsan, Gilani's lawyer, has expressed confidence his client will be cleared.
"The prime minister will survive," Ahsan said before Gilani's court appearance last month.
"There will be no storm," he said on GEO-TV, a Pakistani news channel.
Ahsan is one of the most prominent and widely respected lawyers in Pakistan. He led the so-called "lawyer's movement," an uprising in 2008 that helped bring about the reinstatement of the current Pakistani chief justice, Iftikhar Muahmmad Chaudhry, and dozens of other judges who were sacked by Musharraf in 2007.
Analysts said they believe Ahsan carries considerable influence in the Supreme Court because of his efforts to restore Pakistan's judiciary.
CNN's Becky Anderson contributed to this report.