Sun has been at odds with his own city council from the day he took office in 2012, after winning a write-in campaign in which he vowed to clean out what he called "corruption" at City Hall.
Five of the city's eight department heads either quit or were fired in the following days, and Sun even went to the lengths of placing a padlock on the door to the city clerk's office as chaos and confusion reigned in city government.
The Supreme Court justices agreed with an earlier trial court ruling that there were two grounds for a recall effort against Sun.
The first count is that he allegedly directed his police department officers to operate as his own personal police force by ordering them to conduct a criminal investigation into the identity of those who wrote a negative pamphlet about his Oregon property. Such an order is outside the police department's jurisdiction, the court ruled.
The second count alleges that Sun had jeopardized the city's liability insurance coverage by not filling vacant department head positions.
"If the voters believe these allegations to be true, the allegations show that Sun exercised his discretion in a manifestly unreasonable manner," the trial court ruled, and the Supreme Court justices agreed.
Sun's attorney argued that the mayor has simply been trying to clean up the city and has done nothing wrong.
Now that a recall effort has been approved, Pacific residents will need to gather enough signatures to put the recall to a vote.
That effort will begin immediately, said recall supporters.