The best obstructionist question is ‘who gave you the authority to…?’ My answer is always the same ‘Nobody’
Authority is not given. Authority is earned. Rank & title might be given to you but authority comes from action.
Authority is purpose, capability, experience and leadership rolled into one. You don’t get that without work (& hard work at that). People allow you authority when they have confidence in your leadership to deliver. Authority comes when others chose to follow.
My experience is that when everyone is standing around the empty white space where a problem resides, the person who first steps in to solve it wins authority. Almost always people are relieved that someone did something. That initial authority will grow if you keep delivering on the work to solve the problem.
Don’t wait to be given a parchment & seal with formal authority to act as a leader should. Waiting around is the surest way to lose what authority you have earned.
You have the authority because you want or need to act. It’s up to you to convince others to let you continue. That’s what leaders do.
So do it.