This looks like a leaf spot disease, possibly Septoria on cardinal flower.  The wet weather has been great for fungi.  We suggest that you pick the affected leaves off.  It will probably recover when the weather dries out.  Give the plants space for good air circulation.  The spores for the disease out always out in the environment.  If you get all the affected leaves pulled off, the plant will probably not significantly contribute to the amount of disease in your garden.  vw