Liberal excuses are lame excuses given by liberals when they have been caught and publicly exposed in their misbehavior after it becomes impossible to continue to deny having committed the acts in the first place.
Rather than taking responsibility for what they have done and accepting the consequences, they tend to either downplay the significance of their actions or deflect the blame for them onto others.
When Democrat Eric Massa was caught having homosexually harassed members of his congressional staff and resigned, he tried to place the blame for his resignation onto fellow Democrats. Appearing on the Glenn Beck TV show, he finally took responsibility for his resignation and the actions leading up to it, but then besmirched the U.S. Navy and the rest of the military by suggesting that his behavior was typical Navy behavior. Meanwhile, Nancy Pelosi tried to shield Massa from accountability by suggesting his recent illness was the cause of his actions.
When Harlem Democrat Charlie Rangel was exposed for his nefarious schemes involving rent-controlled apartments in New York, other units in the Dominican Republic, and attempts to avoid legal taxation, he took to the floor of the House of Representatives to whine about racism, and shortly thereafter attended a birthday party headed by Al Sharpton. The Harlem Democrat went on and on about various conspiracy theories, but he never stepped up to take responsibility for his own lapses in judgment. Meanwhile, Sharpton continued to blame alleged racism for Rangel's difficulties.