Paul Manafort, a former campaign manager for Donald Trump, is shown at the Republican National Convention in Cleveland last month. AP

Donald Trump holds a roundtable meeting with the Republican Leadership Initiative in his offices at Trump Tower in New York on Thursday. AP

Not long after I was spokesman for the New Hampshire Republican Party, I deployed to Afghanistan during the height of Operation Enduring Freedom.

It was there that I saw American and NATO sacrifice the likes of which Donald Trump, because of his five draft deferments, has never even come close to seeing – his comments that he has sacrificed by building “great structures” notwithstanding.

It was in Afghanistan that I was presented with a bracelet (that I still wear to this day) by brave members of a Lithuanian military Provincial Reconstruction Team that was leading efforts in a tough, far-flung province to make Afghanistan a safer and more secure country.

Lithuania, a member of NATO since 2004 and one of the small Baltic countries that Trump recently equivocated on whether it was worth defending while implying the country was “not paying its bills,” has sacrificed more blood and resources in the Afghan and Iraq wars than Trump could ever hope to realize.

After all, one would have to understand what sacrifice truly means to even begin to understand why Lithuanians have fought side by side with the United States in two wars and countless counterterrorism operations over the past two decades.

The only time that NATO’s Article 5 clause – which specifies an attack on one NATO member as an attack on all members – has been invoked was after the 9/11 attacks in the United States. It was then that NATO countries came to the aid of the United States, not least of which by assisting with American military efforts in Afghanistan.

If Trump understood the basics about U.S. foreign policy, he would have known that NATO has been fighting terror directly for 14 years instead of saying that “NATO is obsolete because it’s not taking care of terror.” He would have also known that NATO countries such as Lithuania are sending military and police instructors to Iraq as part of the anti-ISIL coalition and are increasing their troop commitment to Afghanistan by more than 30 percent this year.

While Trump’s knowledge of NATO, the most successful military alliance in history, is sorely lacking, it is his campaign’s views on Ukraine and Russia that are willfully ignorant to the point of being sinister.

Trump’s stance that Russia “is not going into Ukraine” is more troubling because it not only denies an obvious current reality but it reflects a calculated and crafted view by former Trump campaign manager Paul Manafort – someone who I had the distinct displeasure of working against during the last decade in Ukraine when he worked on polishing the horrible international image of a Russian-sponsored thug while I worked for the International Republican Institute to assist Ukraine with democratic development.

Even though Manafort is gone, the policy damage he inflicted to the Trump campaign and the Republican Party writ large will have a lasting damaging effect, such as the internal Republican fallout from Manafort’s insistence that the Republican National Committee hollow out its platform on support for Ukraine at the Republican convention in Cleveland.

While this episode received scant attention from the press, inside the Republican Party it sent major shockwaves and led to longtime GOP operatives such as myself to not only not support Trump but to back Hillary Clinton.

As a diehard Republican who has worked for the RNC, IRI and numerous Republican presidential campaigns in New Hampshire, I never would have imagined that I would be supporting Hillary Clinton for president, but Trump is simply too divisive domestically and his world view too dangerous to stay silent.

Clinton has the experience in dealing with complicated countries such as Russia and Ukraine and will continue to support our NATO allies as they have done for us for almost seven decades.

Unlike Sen. Kelly “I support but don’t endorse” Ayotte, I cannot simply roll my eyes and wish that Trump and his divisive rhetoric would just go away. To remain quiet would betray friends of mine I was with in Afghanistan (and Iraq), from countries such as Lithuania, who have fought side by side with American troops defending the values of the United States. It would also compromise the very principles of why I originally joined the Republican Party.

(Mark Lenzi, former spokesman for the New Hampshire Republican Party, has worked on numerous Republican presidential campaigns and is a former Fulbright Scholar in Lithuania. He is owner of Seacoast Steel Network, a New Hampshire-based business.)