As Republicans, we are lucky to have a large and diverse field of presidential candidates that will look voters in the eye and explain why they would be the best commander-in-chief. They don’t duck the hard issues; they take them on directly, and that’s exactly the kind of leadership we need right now.

The polar opposite is true for the Democrats. They have already coronated Hillary Clinton as their party’s nominee, despite the fact that she has shown a fundamental lack of respect for the New Hampshire style of campaigning that requires candidates to make themselves open and available to both voters and the media.

At her most recent town hall in Nashua, for example, Secretary Clinton was asked a very basic yes or no question about her support of the Keystone Pipeline. Instead of an answer, the voter was left with empty rhetoric and a total avoidance of the issue.

With a field of 17 candidates, GOP voters across New Hampshire are no doubt going to pick sides and advocate on the behalf of a particular candidate, as they should. But, if we are going to beat Secretary Clinton next fall, we have to be united as a Party, and that starts with conducting our primary in a courteous and respectful manner. We can’t have Republican presidential candidates resort to mudslinging and vicious attacks, because that will only make us weaker as a party, and increase the odds of Hillary Clinton stealing this election.

If we are going to beat Secretary Clinton next fall, we have to be united as a Party, and that starts with conducting our primary in a courteous and respectful manner.

Democrats know that they cannot defend Secretary Clinton’s abysmal record, particularly during her time at the State Department. Whether it was the failed Russian "reset," the missed early warning signs on the threat posed by the terror group Boko Haram, or her lack of transparency with her emails, which are now facing a potential criminal investigation, it is clear that Hillary Clinton is neither honest nor trustworthy, and she’d continue the failed Obama foreign policy that has weakened America.

To try and compensate for their deeply flawed candidate, Democrats are going to work to fracture the GOP, creating infighting within our party that allows Clinton to win the White House, and expand upon the disastrous policies of the past seven years.

As a party, we cannot let that happen. It is healthy for us to have a vigorous debate among all our candidates about the challenges that our country needs to address, but that debate needs to be focused on the issues, not on trying to tear down fellow Republicans, because that plays right into the Democrats hand. If we are going to beat Secretary Clinton, our party needs to be completely unified behind whomever becomes the Republican nominee.

Make no mistake; all the candidates running for the Republican nomination would be far superior as president than Secretary Clinton. What we must commit to doing is supporting that nominee so they have the full weight of our party behind them, giving them the support they need to win back the White House and start moving America in the right direction.

Ronald Reagan’s 11th Commandment was, “Though shalt not speak ill of any fellow Republican.” Though our party’s presidential candidates are bound to disagree on some of the issues, all of them must run this race with an eye towards the ultimate goal, which is defeating Hillary Clinton, and that starts with having a Republican primary that is civil in nature. 

Scott Brown served for three years as the Senator from Massachusetts. He was a Ranking Member of Armed Services and Homeland Security and also served on the Veteran’s and Small Business Committees. He is a Contributor with Fox. Follow him on Twitter @senscottbrown.