Massachusetts Assistant Attorney General Peter Sacks has moved to throw out a case where the state Republican Party is attempting to block the late Sen. Edward Kennedy's interim replacement from being sworn in. 

Gov. Deval Patrick appointed long-time Kennedy family friend Paul Kirk to the seat Thursday.

Sacks says Patrick was within his authority to name Kirk and make the appointment effective immediately.  

He added that because of the government separation of powers principle, the judge hearing the case cannot delay the appointment.
 
The bill giving the governor the power to make the appointment was passed this week. Although laws customarily take 90 days to go into effect, Patrick signed a letter of emergency for the law to take effect immediately.
 
Republicans, meanwhile, are not pleased arguing that Patrick overstepped his constitutional authority. 

Kirk is scheduled to be sworn in on Friday.