If a writer wanted to introduce conflict in a scene without using an antagonist which would be most effective

I would say maybe the author makes one of the main characters lose a shoe or falls on the ground and has to go to the hospital. as these things arnt people or animals so they won't be considered antagonists.

the answer to your question is a because laws act as guidelines as to what is accepted in society. without it there would be conflicts between social groups and communities. it serves as a norm of conduct for citizens.

"this speech"? what speech are you talking about?