On Tuesday night, Indiana Governor Mike Pence deflected blow after blow from his opponent, Senator Tim Kaine of Virginia, in the 2016 Vice Presidential Debate. Kaine repeatedly referenced controversial comments made by the governor’s running mate, Donald Trump, including the businessman’s badmouthing of Senator John McCain’s military service.

Since being chosen as Trump’s running mate, Pence has specialized in damage control, softening extreme comments made by Trump and broadening the appeal of the Republican ticket. With Trump’s ceaseless blunders, one would think that Pence could not correct his running mate’s every mistake, especially when Trump is so unpredictable.

However, Trump’s polling numbers have been, for the most part, consistently competitive. Since May, Trump has remained, on average, within 10 points of his competitor, Hillary Clinton, according to RealClearPolitics. He currently polls at about 44.2 percent of the vote on average, compared to Clinton, who polls at 48.1 percent. In spite of hateful rhetoric and alienation of several voter groups, the two candidates are essentially tied in the polls.

Is there nothing that damages the Republican candidate’s viability? Can he say anything and expect the voters to back him?

This candidate has made misogynistic comments about women, called Mexican immigrants rapists and claimed the Chinese invented global warming. He suggested President Barack Obama is not eligible for office, a myth that persists today, and has individually besieged countless people from his Twitter account. Although many people loathe Trump and detest his remarks, his voter base remains intact.

Pence isn’t as effective at damage control. Trump, rather, survives each mistake because his voters frame these comments not as bigotry or unpreparedness, but as their candidate being forthright. Donald Trump says what he means.

Another dimension of Trump’s voter base is their distrust of Clinton and the political establishment to which she belongs. In this way, Trump’s candidacy is a protest of American politics. Americans are willing to dismiss his controversial comments by focusing on their distaste for Clinton. They think she is corrupt and ineffective. These Americans, fed up with the same political procedures, want drastic change in government and expect Trump to accomplish this.

What breaks Trump are attacks from people who identify with his base. Established elites can’t touch him. His supporters look at them and see bias. People like the Khans, a Gold Star family, can hurt Trump, especially when they bait him into attacking the identities of his base.

Trump criticized the Khans, the Pakistani-American parents of United States Army Captain Humayun Khan, who was killed in Iraq in 2004. He suggested that Mrs. Khan was unable to speak at the Democratic National Convention because of her religion, despite her saying that she didn’t want to speak—talking about her son’s death made her cry. He compared his business prowess to military service, claiming this was sacrifice.

In polls following his criticism, his numbers plummeted. On July 27, his polling average was 45.7 percent, but by July 9 the average dipped down to 39.9.

Clinton has managed to maintain a low profile and let Trump hurt himself for the most part. She has much more to lose when it comes to making mistakes, and she is held to a much higher standard. However, Trump’s attack on the Khan family displays his vulnerability.

Although his numbers have climbed since August, Trump’s attack on military personnel reveals his weakness. If Trump alienates his base, such as those involved in the military, he loses support. Republicans already do not carry African Americans and Latinos, so losing them will not strongly impact him this far into the race. If Clinton can lure Trump into damaging his relationship with his base, however, especially military personnel, he will be hurt much worse.

Trump may elude the restraints of normal politicians, but his interaction with the Khan family demonstrates he is not invincible. Even the masterful damage control of Mike Pence won’t protect the Republican ticket from alienation of the conservative base.