I was written up at work accused of making a statement I didnt but that another employee made and admitted to?

With the employee who made the statement and another witness besides myself all confirm that I did not make a statement saying something about this is America and people should emerse themselves in to it because it is America. I dont talk in that manner. The person who made the comment close to that statement admitted to the comment. A bypassing employee over heard, told my supervisor it was me and I got talked to with a high pitched voice and threatened that I would be written up for causeing a hostile work place. I stated I did not make the comment and who infact did. My supervisor pulled that person in telling them in words...I threw them under the bus. They admitted to saying it and confirmed it was not me. The other employee who was involved in the conversation as well stated when called in that it was not me who made the comment. I was then called back in, written up and told I understand your husband is previous military and you are proud Americans but keep it to myself. REALLY? How should I handle this. Mind you for the last 8 months there has been nothing but drama, harrassment, lies and trouble within our building trying to get others in trouble. Its a hard to go to work most days if not all!