President Donald Trump speaks aboard the pre-commissioned USS Gerald R. Ford aircraft carrier in Newport News, Virginia, March 2, 2017.

In a politically unsettled nation, military communities have long been a rock for the Republican Party, solid and true. But new polling data suggest those places have developed some concerns about President Donald Trump.

An analysis of Gallup polling data comparing the first 100 days of Trump's presidency to the month of May shows that Trump's job approval in military counties dropped sharply in the last month — from an average 51 percent approval and 41 percent disapproval in the first 100 days to 43 percent approval and 52 percent disapproval for May.