Although it will be a while before each party's eventual nominee picks a running mate, there are no shortage of choices -- both realistic and more far-fetched. There are even a few who have been pitching themselves for the job.
Here's a look at some of the potential contenders for the No. 2 slot on the presidential ticket:
2. Oprah Winfrey
3. Carly Fiorina
Fiorina, the only woman currently competing for the Republican presidential nomination, recently dismissed speculation that she could receive a VP nod, saying the notion was sexist. "It would be different if all of the other candidates were being asked that question over and over, so one could only conclude that I am being asked that question because I am a woman, which is disappointing because I don't sense that from voters," Fiorina told Fox News in early September.
4. Charlie Sheen
Despite slamming Donald Trump on Twitter in July, actor Charlie Sheen is interested in running for vice president. In a tweet last month, Sheen says if asked, he would be the GOP presidential nominee’s vice president in a ‘heartbeat.’
5. Nikki Haley
Similarly, South Carolina Gov. Nikki Haley announced that she too, would consider joining the Republican ticket if asked by the party’s nominee to run for vice president. At an appearance at the National Press Club in Washington, Haley said she would not spend time thinking about the GOP ticket -- but she did not dismiss the idea of becoming a running mate. “If there is a time where a presidential nominee wants to sit down and talk, of course I will sit down and talk,” Haley said in response to audience questions. When asked about being Donald Trump’s vice president, specifically, Haley responded by saying, “That is so wrong whoever sent that question up.”
6. Jim Jatras
You may not have heard of Jim Jatras, a former Senate Republican staffer and former U.S. diplomat from Virginia, but he wants a spot on the presidential ticket too. He unexpectedly decided to tell the top 16 Republican candidates about his interest in the vice presidency on Wednesday, proclaiming on Twitter that “we need to feel like Americans again."
Jatras describes himself as “pro-life, pro-gun, pro-traditional marriage, pro-immigration control, anti-war, pro-privacy, pro-tax reform, anti-phony ‘free trade’ deals.” He is currently the editor of RepealFATCA.com, which campaigns against the Foreign Account Tax Compliant Act, passed in 2010.
7. Ben Carson
Carson, who is currently running for the top spot, is nipping at Trump's heels in the polls, but he hasn't ruled out the possibility of becoming his rival’s running mate. When asked by CNN whether he would consider service as Trump’s vice president, Carson said “all things are possible, but it is much too early to begin such conversations.”
8. Kelly Ayotte
9. Hulk Hogan
After wrestling against racist remarks that ended his contract with WWE earlier this summer, Hulk Hogan shared in an interview with TMZ that he was not upset with the organization for cutting ties with him. Instead, Hogan announced his interest in taking on a new role, joining Donald Trump as his vice president, in an effort to make America great again. When a fan took to Twitter to encourage Hogan to run for president he responded by saying, “If Trump wants the people’s vote maybe I should be his VP, brother. HH.”