Bisexuality is the recognized sexual orientation being attracted to both male and female genders. It does not mean that a person cannot make up their mind on who they want to have sex with, but just means that they are attracted to both males and females. They don't have to be attracted to both sexes equally either, as some are more attracted to the opposite sex than the same sex (i.e., have a lower Kinsey number), and some are more attracted to the same sex than the opposite sex (i.e., have a higher Kinsey number). Note that lying about your sexual orientation to secure Republican votes will not decrease your Kinsey number, but will guarantee that everyone from both sides of the aisle sees you as little more than a lying, ignorant, bigoted asshole. See the slightly different pansexuality, which means a person is attracted to both genders equally.
If you take a look at the Conservapedia page on bisexuals, you will see that the only picture they have is of occultist Aleister Crowley. Which is kind of like a slap in the face to bisexuals, relating them to occultists. But hey what do you expect its Conservapedia.