What is the role of special interest on presidential campaigns?

Ineed to have answers for numbers 2-4 reply to this question

Me < 3 there are multiple ‘3rd party’ political parties in the us. what are the benefits of having 3rd parties? what are the disadvantages of being a member of one? would the u.s. benefit if there were more 3rd parties created, more support for the current ones, or would it be best to get rid of them altogether? why?

Which of the following was not an organization during the civil rights movement in the 1960s