haha, this is a joke question isn't it? Honesty, firm on principles, intelligence? look up the criminal records of these politicians and former politicians...
It's most important to be a team player. Nothing gets done in Washington without major amounts of cooperation and support. You need to be able to get people working together if you hope to get anything done, and being a team player yourself goes a long way toward that.
Honesty and consistency. It really irks me that two of the most inconsistent politics (one a pathological liar) are the two presidential nominees. But I guess that's how America works: voters favor whichever politicians tell them what they want to hear the most, regardless if it's the truth or consistent with their previous political stances.