I assume you are asking from the perspective of the governing party? There is a strategic aspect to it. If you assume that your position will become worse in t

I assume you are asking from the perspective of the governing party? There is a strategic aspect to it. If you assume that your position will become worse in the future you want to capture the moment. This is commonly done from a position of strength. When the opposition is in tatters and your poll numbers are great you want to "lock" the numbers in. I'm not sure if that logic applies now. Maybe they suspect their polling will get worse with time?