The 5 Fiercest Rivalries of the 2016 Presidential Campaign

With the 2016 race for the White House heating up, the gloves are coming off.

ByABC News
October 3, 2015, 8:34 AM
Bobby Jindal speaks in Ames, Iowa on July 18, 2015 and Donald Trump speaks in Dubuque, Iowa on Aug. 25, 2015.
Bobby Jindal speaks in Ames, Iowa on July 18, 2015 and Donald Trump speaks in Dubuque, Iowa on Aug. 25, 2015.
AP Photo | Getty Images

— -- With the 2016 race for the White House heating up, the gloves are coming off.

With 15 Republican candidates and seven Democrats still in the running for their party’s nomination, the crowded field has created fierce rivalries.

While the debates have offered the candidates an opportunity to confront each other face-to-face, many have been throwing punches on the campaign trail on everything from their opponents’ politics to personality.

Here is a look at the five most contentious rivalries so far this campaign season:

Bobby Jindal vs. Donald Trump

Hate is a strong word, but it’s safe to say Louisiana Gov. Bobby Jindal “really, really, really” (his words) doesn’t like the GOP front-runner, Donald Trump. Jindal has made discussing Trump a central talking point of his campaign, both on social media and on the road.

The real estate mogul was quick to the punch, showing no mercy for Jindal.

Despite Trump’s response, it seems Jindal will continue attacking the Republican front-runner.

PHOTO: Marco Rubio, left, and Jeb Bush.
Marco Rubio, left, and Jeb Bush.

Jeb Bush vs. Marco Rubio

Although longtime friends Jeb Bush and Sen. Marco Rubio have plenty in common (both are Miami Dolphins fans, fluent in Spanish, and experienced in navigating Florida state politics) the 2016 Republican presidential candidates are trying to set themselves apart. Bush in particular has been on the offensive. This week, as Bush made the cable news circuit, the former governor of Florida made the case that his rival, Marco Rubio, lacks the leadership experience necessary for the White House.

During an interview with CNN’s Dana Bash, Bush likened the 44-year-old senator's appeal to another young senator who ran for office, Barack Obama.

"Look, we've had a president who came in and said the same kind of thing — 'new and improved,' 'hope and change' — and he didn't have the leadership skills to fix things,” said Bush.

Bush also suggested that Rubio is more of a protégée than a potential rival. When asked about Rubio’s leadership on MSNBC’s “Morning Joe,” Bush said, “Marco was a member of House of Representatives when I was governor and he followed by my lead and I’m proud of that.”

Rubio on the other hand has not engaged in tit-for-tat candidate criticisms with Bush. But that could change soon as Rubio and Bush, the two establishment Republicans, court similar donors. While their polling numbers are neck and neck, Rubio is currently trailing Bush in fundraising. And when money’s involved, the gloves might finally come off.

PHOTO: Ted Cruz and Rand Paul have been attacking each other during the campaign.
Ted Cruz and Rand Paul have been attacking each other during the campaign.

Ted Cruz vs. Rand Paul

As the presidential race heats up, it’s no surprise that some candidates are going from political allies to rivals. Case in point: Sen. Ted Cruz and Sen. Rand Paul. The Kentucky senator who once introduced Cruz as a “friend,” described the Texan differently in a recent interview with Fox News Radio.

“Ted has chosen to make this really personal and chosen to call people dishonest in leadership and call them names which really goes against the decorum and also against the rules of the senate and as a consequence he can’t get anything done legislatively,” Paul said. “I approach things a little different, I am still just as hardcore in saying what we are, I just chose not to call people liars on the Senate floor and it’s just a matter of different perspectives on how best to get to the end result.”

Cruz responded to the personal attacks in an interview with Hugh Hewitt's radio program on Wednesday.

“None of this is personal. The media loves to characterize it as a battle of personalities, as a soap opera. Look, I think most Americans could care less about a bunch of politicians in Washington bickering like schoolchildren. It doesn’t matter and so if others attack me, I don’t reciprocate. I will not throw rocks.”

Despite Cruz’s response, his campaign seems to be doing the work, releasing a video featuring several libertarian-minded supporters of Paul’s father and former presidential candidate, Ron Paul, who are now backing Cruz.

PHOTO: Martin O'Malley is pictured on Aug. 14, 2015 in Clear Lake, Iowa.
Martin O'Malley is pictured on Aug. 14, 2015 in Clear Lake, Iowa.

Martin O’Malley vs. the Democratic National Committee

Democratic presidential candidate Martin O’Malley routinely takes on Hillary Clinton, but his biggest white whale of 2016 appears to be the Democratic National Committee and its debate schedule.

There are only six sanctioned opportunities for Democratic presidential candidates to duke it out this cycle, down from 26 Democratic debates during the 2008 presidential election -- and O’Malley is not happy about it.

“We need debate” has become the former Maryland Governor’s battle cry. More recently at the DNC’s summer meeting in August, O’Malley argued the debate schedule was “unprecedented” and a “rigged process” made to benefit Hillary Clinton.

Some members of the O’Malley campaign -- including his campaign manager -- protested outside the DNC’s Washington, D.C. headquarters during the night of the second Republican debate. DNC Chairwoman, Debbie Wasserman Schultz, has so far remained firm in her decision to keep the debates capped at six.

PHOTO: Cary Fiorina and Hillary Clinton
Carly Fiorina, left, speaks at the Conservative Political Action Conference, March 8, 2014. Hillary Clinton presents her autobiography 'Hard Choices' in Berlin, July 6, 2014.

Carly Fiorina vs. Hillary Clinton

The only two women running for president, Hillary Clinton and Carly Fiorina are often compared to each other.

Fiorina kicked off her campaign by attacking Clinton creating a website, ReadyToBeatHillary.com. In August, Fiorina published an op-ed on CNN.com sharply criticizing Clinton’s time as Secretary of State. “Throughout this campaign, I have repeatedly asked Hillary Clinton to name an accomplishment,” wrote Fiorina. “She has yet to name one.” And during the second Republican presidential debate in September, Fiorina quipped, “if you want to stump a Democrat, ask them to name an accomplishment of Hillary Clinton.”

While Fiorina criticized Clinton’s track record as senator of New York and Secretary of State, Clinton responded by saying “If anyone is interested, there is a long list of what I’ve done and I’m very proud of it.”

But after a summer of attacks, is Fiorina starting to go soft? In a People magazine interview last week, Fiorina came to the defense of her political rival.

"I feel empathy with every woman who is working really hard and giving it all they've got – and Hillary is," Fiorina said. "She's smart, she's hardworking, she's giving it all she's got."