U.S. Senators Rand Paul (R-Ky.) and Ted Cruz (R-Texas) are the first two candidates to officially announce their candidacy in the 2016 presidential election. They are two of the most interesting, dynamic, and polarizing figures in American politics today.

Both men have striking similarities in their approach to politics and governing, as well as the voters they appeal to. However, there are also several key differences between the two that will distinguish and define their presidential campaigns.

1. Voter Outreach

One of the most notable differences between Rand Paul and Ted Cruz is their style of campaigning, and how they communicate with voters.

During his time in the Senate, Cruz has always stayed pretty close to his conservative base and has tried to rile up conservatives from within the party. For example, in March, when he announced the launch of his 2016 campaign, he did so at Liberty University, the largest Evangelical Christian university in the world.

During his announcement, Cruz's rhetoric echoed a base-heavy approach to campaigning when he said, "I believe in the power of millions of courageous conservatives rising up to reignite the promise of America."

Senator Paul, on the other hand, has attempted to reach out not just to conservatives, but a broader range of Republicans and voters who do not traditionally vote for Republican candidates. On March 23, Paul told Fox News host Megyn Kelly:

"I'm a big believer that you stand on principle, and be true to your principles, but I also think we should take those principles and try to bring in new people." - U.S. Senator Rand Paul (R-Ky.)

For that reason, Paul has made strong efforts to reach out to minorities and crowds that are typically defined as "more liberal," visiting and giving speeches at places like Berkeley, Detroit, Ferguson, and Howard University.

2. Legislation

Similar to their outreach and campaign style, Paul and Cruz differ on some of the legislation they have proposed and advocated.

Cruz focuses solely on the issues that infuriate conservative voters. This includes things like defunding and/or

repealing Obamacare, repealing Common Core Standards (which is not a federal law), securing the southern border, providing proof of citizenship during voter registration, increasing funding for the missile defense shield, and opposing numerous gun control proposals.

By supporting these kinds of bills and policies, Cruz is building up his credentials as the new "Mr. Conservative" in an attempt to rile up GOP voters.

While Paul has certainly sided with hardline conservatives on issues like Obamacare and illegal immigration, he has also taken up issues that are vastly different from the ones Cruz is dealing with. In the past few years, Paul has extended his message of liberty to legislation that would reform prisons, restore voting rights and welfare benefits to ex-felons, and legalize medical marijuana by teaming up with colleagues across the political aisle, such as U.S. Senator Cory Booker (D-N.J.)

Rand Paul has shown a willingness to work with lawmakers outside the Republican Party that voters have yet to see from Ted Cruz.

3. Foreign Policy

Another huge difference between Rand Paul and Ted Cruz is their philosophical approach to foreign policy.

It's no secret that Rand Paul has been both highly praised and highly criticized for his non-interventionist views. He has been called weak on national security -- especially among conservatives. Paul believes that the U.S. should not be the policemen of the world and that intervening in world affairs has not been a wise policy choice in recent years, echoing a lot of what his father, former U.S. Representative Ron Paul (R-Texas), is known for saying.

Cruz, however, while agreeing with Paul on the nation's drone policy and mass surveillance for counter terrorism, has tried to distance himself from Paul when it comes to U.S. intervention. Cruz has made it clear that he doesn't think we should simply deploy troops everywhere for any reason, but he does feel that the U.S. should have a strong leadership role in the world, and advocates a more aggressive policy.

In an interview with ABC News in 2014, Cruz went out of his way to distance himself from Paul on this issue, saying, "I'm a big fan of Rand Paul. He and I are good friends. But I don't agree with him on foreign policy."

4. Electability

When it comes to distinguishing Rand Paul from Ted Cruz, one of the biggest differences between the two men has to be electability. While both are strong conservative candidates who can excite the base, electability is key.

Cruz has made huge efforts to appeal to conservatives within his party, which has helped him in

primary elections, but might not be so helpful in a general election on the national stage. Paul, conversely, has made efforts to draw in conservatives, but also has gone to great lengths to reach out to Millennials, African-Americans, and Latinos.

As a result of the two different tactics, Rand Paul appears to have a slight edge over presumed Democratic frontrunner Hillary Clinton. According to a recent CNN/ORC poll, Paul stands the best chance against Clinton at 43 percent, leading every other Republican in the poll.

Rand Paul told Fox News in March that while Ted Cruz is conservative, it all comes down to who can win. It is not only about who can excite the base, but who can bring in new people as well.

Rebecca Berg summed up this difference in an article for the Washington Examiner, writing:

"While Cruz fights over ideology, Paul leads a rising libertarian faction within the party. Cruz rallies activists outside the Beltway. Paul focuses on policy and earned a reputation in the Senate for working within the body’s traditional framework and with quiet consideration for colleagues."

The differences between these two stars in the Republican Party are pretty substantial and with Rand Paul announcing his run for the presidency on Tuesday, it will be interesting to watch how the two interact during the primary season.