You have the right to place electioneering signs on the property you lease.
That is, if the lease doesn't prohibit it.
I doubt that is does.
You can take your landlord to court and sue him over this.
What will you receive?
Maybe a few dollars and the right to place the sign.
Most likely, however, the election will be over.
So, why hurt yourself and your family over this?
The landlord can't order you to take the sign down.
But, you are better off to take the doggone thing down.
You can discreetly tell the candidate that it was causing you trouble.
Tell him you'll vote for hi (if you plan to do that), but had to take the sign down to make your landlord happy!
That way you can continue to live peacefully in these difficult times.
But, if the guy gets elected, you've got a friend in the High Sheriff!!!
You also keep your meddling landlord off your back!