Marc Racicot is a former governor of Montana and former chairman of the Republican National Committee.

As our beloved country marks its 240th birthday, I’m not alone in feeling that we occupy a moment of great turmoil and testing as a nation. Maybe we’ve taken the wonders and blessings of our country for granted, never thinking the grand experiment of our Founding Fathers, so dependent for its endurance upon mutual decency, respect and self-discipline, could ever really fall into disrepair.

Throughout history our republic has faced other extraordinary threats to our freedom, our existence as a nation and our system of self-government. But in those times, by the grace of God, the nation has been blessed with the emergence of good and courageous men and women of character and fortitude who have led “this last best hope of man on Earth” through harm’s way.

One of the most profound examples of such leadership was provided by Abraham Lincoln, the father of the Republican Party and, many would say, our most distinguished president. But Lincoln was not always perceived that way.

Although he served several terms in the Illinois state legislature and one term in Congress, Lincoln was also defeated in U.S. Senate campaigns in 1854 and 1858. Nonetheless, he became one of four presidential candidates in 1860, representing a new party that formed during some of the most fractious moments in our history. Lincoln was elected our 16th president with only 40 percent of the popular vote.

Donald Trump said he raised $6 million for veterans – but months later, much less had been distributed to vets' groups. (Peter Stevenson/The Washington Post)

How is it that, in the darkest of times, the nation invested its confidence in a man who had failed in business and had lost almost as many elections as he had won, a man who had no significant administrative experience, a man who represented a new political party that had never seen the inside of the White House, and a man who was not even the first choice of his party on either of the first two ballots of that party’s political convention in 1860?

There appears but one conclusion. The collective whole of our citizenry, like a jury, has always had the capacity, if the evidence was before them, to discern those best qualified by virtue of their character and capacity, to lead us through perilous times.

As responsible, though admittedly not perfect, citizens, we are obliged, before automatic commitments to political parties, ideologies or candidates, to give consideration to those timeless and eternal qualities of genuine leadership that transcend ever-changing political charters, programs and affiliations. Rarely stopping to inventory them, we all know them when we see them.

It is inescapable that every decision made by every leader reflects the character of the man or woman making the decision. Character is the lens through which a leader perceives the path to be followed. It conceives and shapes every thought and is inextricably interwoven into every word spoken, every policy envisioned and every action taken.

Persistent seriousness, solemn and honest commitment to the interests of others, exhaustive study and detailed proposals, sincerity, humility, empathy, dignity, fairness, patience, genuine respect for all of God’s children, durability, modesty and the absence of self-interest are those qualities of principled leadership absolutely essential to presidential decision-making.

Knowing my own imperfections and frustrations, I am hesitant to judge others harshly. And I know that 13 million people, my fellow citizens, have made their initial choice in voting for Donald Trump, thereby elevating his candidacy to presumed nominee. I don’t deny nor diminish the message that each of those votes carries with them. And every one of those 13 million people has a right to be heard and their thoughts fairly and honestly considered.

But after long and careful consideration, I cannot endorse or support their decision to express their frustration, anger and disappointment by selecting Trump as the Republican nominee for president. Trump has demonstrated neither the aforementioned qualities of principled leadership, nor offered any substantive or serious conservative policy proposals consistent with historical Republican Party platform positions. Both, in my humble view, are indispensable preconditions to his selection as the Republican candidate for the office of president of the United States.

As a result, I cannot endorse or support Trump for president. And I offer my prayer for a second miracle in Cleveland.