Republicans currently control the Senate 51-49.Democrats need to flip at least two seats to become the majority, which would give them the ability to block additional Trump appointees to federal judgeships and a stronger hand in legislation. But gaining those two additional seats is a tall order.The 35 Senate races this year include a disproportionate number of Democratic incumbents trying to hang on in conservative states. With 29 seats to defend, compared with just six for the GOP, Democrats will be hard pressed to avoid losing ground, much less gain any.