NBC NATIONAL NEWS — A California court of appeals has upheld a lower court ruling that the state's voter approved Proposition 8 ban on same-sex marriage is unconstitutional.

"Very soon Prop 8 will be gone forever when that day comes we can celebrate a victory for freedom, fairness and equality. We can't wait for that day, we can't wait," plaintiff Kris Perry said after the announcement.

"This is an important step - we are not at the end of the line yet, but I cannot overstate the importance of the decision today," added attorney Ted Olsen.

The much anticipated decision takes the ongoing public debate and court battles over same-sex marriage one step further down the aisle.

The decision doesn't end the debate, however.

Prop 8 supporters vow to appeal.

Both sides agree it's likely the U.S. Supreme Court will eventually