Donald Trump just got an endorsement from a bunch of generals and admirals

In the 2016 election, Republican presidential nominee Donald Trump has struggled to get solid backing from some influential groups that many believe are part of the typical GOP constituency.

But on Tuesday, he received an endorsement he didn't seem to have to fight to earn.

Retired general-grade officers, some 88 in all, wrote in support of a Trump presidency in an open letter that was published on his campaign website. The letter was organized by Maj. Gen. Sidney Shachnow and Rear Adm. Charles Williams and includes four four-star and 14 three-star generals and admirals.

They argue that Democrat presidential candidate Hillary Clinton is the wrong choice for a strong military and that a Trump White House would restore American ranks.

"As retired senior leaders of America's military, we believe that such a change can only be made by someone who has not been deeply involved with, and substantially responsible for, the hollowing out of our military and the burgeoning threats facing our country around the world," the letter reads, arguing against supporting Clinton.

And Trump was happy to have the senior former military leaders' backing.

"It is a great honor to have such amazing support from so many distinguished retired military leaders," Trump said in a statement on his website. "Keeping our nation safe and leading our armed forces is the most important responsibility of the presidency."

Clinton has received some endorsements from former general officers, including former Marine Gen. John Allen, who was instrumental in helping bring down al Qaeda in Iraq in Anbar Province.

But the letter comes at a time when former flag officers are coming under fire for their overt political support. In a letter to the Washington Post, retired Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey said retired officers made a "mistake" by speaking at political conventions.

The former top military leader criticized retired Gens. John Allen and Michael Flynn for breaking the tradition of retired generals remaining apolitical.

"Politicians should take the advice of senior military leaders but keep them off the stage," Dempsey wrote. "The American people should not wonder where their military leaders draw the line between military advice and political preference. ... And our nation's soldiers, sailors, airmen and Marines should not wonder about the political leanings and motivations of their leaders."

It's not yet known what effect general officers backing Donald Trump in such force will have. With Election Day just nine weeks away, Trump pulled ahead of Clinton by 2 percent in the latest CNN/ORC poll.