A Lame Duck usually refers to a politician who is serving the end of their term and will not be serving another term. This may be because they didn't receive reelection or because they have reached the term limit for their position. Whatever the reason, not having to worry about reelection means that these politicians no longer have to be accountable for their actions. This gives them more freedom to do whatever they want. The date celebrates the passing of the 20th amendment to the US constitution, which moved the date of inauguration of a new president from March to January, reducing the amount of Lame Duck time for the previous president.