Watch | Tim Kaine and Hillary Clinton don't see eye to eye on everything
Right now, they're best known for who they stand behind on the campaign trail.
But when Sen. Tim Kaine (D-VA) and Indiana Gov. Mike Pence go head-to-head in their first debate on Tuesday night, the vice presidential nominees will get a chance to show who they really are -- and how they might govern differently than Hillary Clinton or Donald Trump should they one day be called to fill the top spot in American politics.
Even before their head-to-head, though, we already know that Kaine and Pence are not entirely like their running mates when it comes to policy.
There are at least three ways each vice presidential nominee differs from their respective running mate. We'll start with Hillary Clinton and Tim Kaine.
While both Kaine and Clinton are pro-choice, Kaine is a Catholic and has said he, personally, is morally opposed to abortion. Clinton, on the other hand, has been enthusiastically endorsed by Planned Parenthood and NARAL Pro-Choice America.
The two nominees also differ on the Hyde Amendment -- the law that severely limits how much federal funding can go toward abortion care. Clinton has said she wants to repeal the Hyde Amendment, while Kaine has indicated he still supports it.
The death penalty
For Kaine, the answer to the death penalty question is simple: No way, no how.
His own history with the death penalty, however, is complicated, as Kaine has not only opposed the death penalty but also actively worked to prevent murderers on death row from being executed.
Clinton has said she feels the death penalty can be discriminatory and that the U.S. should take "a hard look" at it -- but has also said she is "not in favor of abolishing it."
Clinton and Kaine have recently butted heads on the issue of whether the U.S. has the legal authority to launch airstrikes in Libya against ISIS militants.
"I don't think the current legal authorities are sufficient to wage this war against ISIL," Kaine said in an interview in August.
That position differs from Clinton, who has said the legal authority for airstrikes derives from the 2001 Authorization for Use of Military Force -- a law which allowed action against anyone affiliated with the Sept. 11 attacks.
Watch | Mike Pence and Donald Trump aren't exactly peas in a pod either.
Here's how Trump and his lesser-known counterpart differ on the issues.
Much has been written of the fact that, while Trump has based much of his campaign on opposing free trade deals, his running mate has based much of his career off supporting them.
While Trump has called the North American Free Trade Agreement "the single worst trade deal ever approved in this country" and pledged to pull the U.S. out of the Trans-Pacific Partnership, Pence has praised both deals -- and many other free trade deals -- in the past.
One of Trump and Pence's most well-known disagreements came right after Trump proposed temporarily banning all Muslims from immigrating into the United States. In response, Pence -- who was not yet Trump's running mate, sent off a tweet calling Trump's policy "offensive" and "unconstitutional."
Pence has since warmed to Trump's policy a bit, saying he supports temporarily halting immigration from "countries where terrorist influence and impact represents a threat to the United States."
Calls to ban Muslims from entering the U.S. are offensive and unconstitutional.— Governor Mike Pence (@GovPenceIN) December 8, 2015
Here are Pence's original thoughts about Trump's Muslim ban.
The LGBTQ advocacy community and Mike Pence have not had a great relationship.
Pence opposes marriage equality, once spoke in favor of conversion therapy, and voted against the repeal of Don't Ask, Don't Tell. He opposed a law intended to prohibit workplace discrimination against LGBT people, and rejected the Obama administration's directive to allow transgender citizens to use the bathroom that corresponds with their gender identities.
Trump: LGBTQ protector or oppressor?
Trump, on the other hand, has pledged to do "everything in my power to protect our LGBTQ citizens" from ISIS and violence abroad.
At the same time, Trump has said he would "strongly consider" appointing Supreme Court justices who would overturn the court's historic decision to legalize same-sex marriage nationwide.
"I disagree with the Supreme Court," Trump said. "It should be a states' rights issue."