KABUL, Afghanistan — Members of the Afghan Parliament came to blows Tuesday as a majority for the first time began to discuss impeaching President Hamid Karzai, signaling the near-total breakdown of relations between the Parliament and the president as the country teeters on the brink of a constitutional crisis.

The dispute centers on the legality of a special court set up by President Karzai to adjudicate allegations of fraud by candidates who lost their seats or were disqualified in last September’s parliamentary elections. Two weeks ago the special court ruled that 62 members of the current Parliament should be replaced by those who brought challenges, many of whom are allies of the president.

Neither the country’s election authorities nor the international community have recognized the court’s authority, and the prospect of now having to give up their seats has enraged a large bloc of the current 249-seat Parliament. All of the legislators have already been sworn in.

The fight between the Parliament and Mr. Karzai has halted the normal workings of government. Nine months after the election, the president has yet to introduce a transitional government — or to submit proposed legislation for review. He has been ruling by decree and by allowing a number of acting ministers and acting Supreme Court justices to remain in charge.