Like many people, I have been wondering: What on Earth explains Donald Trump’s remarkable appeal to voters?

I’ve come to the conclusion that the answer is fairly simple. The message of his Republican opponents has effectively been: We are more faithful to conservative principles. Trump’s message has been entirely different. He essentially says: I will protect you. I’m conservative, but if protecting you requires jettisoning conservative ideology, I will do so. Protecting you is the prime directive. This message has powerful resonance, especially for voters who feel the Republican Party has failed to protect their interests.

You see this pattern in all of Trump’s deviations from conservative orthodoxy. Take the debate over Planned Parenthood. Like all conservatives, Trump opposes abortions. But he stresses he does not want to stop funding their wonderful work protecting women from cervical and breast cancer. The other Republican candidates simply express a desire to destroy Planned Parenthood outright. Trump’s message to voters: The other candidates will adhere rigidly to ideology, even if it needlessly fails to protect millions of women from cancer. I won’t.

Or consider the debate over Obamacare. Again, like all conservatives, Trump promises to repeal and replace it. But he stresses that he is not going to let poor people die because they lack access to health care. The other candidates say: Aha! Trump is not a purist opponent of government-funded health care. Neither Trump nor his opponents offer many specifics, but the message to voters is that at least Trump’s goal is to protect them from the financial burdens of Obamacare without sacrificing their health. His opponents suggest their goal is just the ideological purge of Obamacare, regardless of the health implications.

On campaign financing, Trump’s message is basic: I am financing myself, so you can trust me to protect you because I will be beholden to no one other than the people who elected me. You can’t trust these other guys to protect you, no matter how good what they say might sound, because they will protect whoever paid for their campaigns. The other candidates, having pledged allegiance to the ideology of Citizens United, have no response and avoid the topic.

Trump’s signature policy is to build a wall to protect his voters’ jobs. What could evoke protection more than building a huge wall? His opponents quibbled about its feasibility but ultimately adopted the same position. Trump’s message to voters: I care about protecting you enough to propose huge historic projects. The other candidates begrudgingly agreed, but their heart is not in it, so they are less likely to follow through.

Free trade is great, Trump says, but it has to be fair. His opponents just adhere to pure free trade, which does increase the economic pie. But economic research shows that free trade harms some subsets of voters, particularly the working-class voters flocking to Trump. The message to his voters: I will favor free trade only to the extent that I can protect you from harm, perhaps by compensating you using the gains of trade. My opponents will favor free trade even if it harms you.

Much the same goes for taxes and entitlements. Trump says he will cut taxes but not cut Medicare and Social Security, while the others favor cutting both. His message to voters: Only I value protecting your retirement benefits over tax cuts.

Trump stresses how much he wants to spend on the military to keep Americans safe. But he loudly criticizes the Iraq War for costing many lives and dollars while making the world more dangerous, and he argues against repeating the mistake in Syria. The other candidates gasp, because he is violating the conservative ideology that the Iraq War was a noble cause, albeit misinformed, and they advocate further noble but bellicose strategies in Syria and elsewhere. Trump’s message to voters: I will use the military to protect us; the other candidates will use the military to advance ideological views about military honor, even if that sacrifices the lives of many of our soldiers for no discernible benefit.

Trump even challenged the gospel of 9/11. In conservative ideology, 9/11 was a time of noble suffering, and all George W. Bush can get is credit for keeping us safe after it. Trump stresses instead that Bush didn’t keep thousands from dying on 9/11. The message: Honoring the fallen is no excuse for failing to protect us in the first place. Protection beats ideology, every time.

The same message pervades his style. Trump talks endlessly about his polls, because the polls stress that he is strong enough to protect his voters. He speaks extemporaneously and often crassly in a stream-of-consciousness way, which has many pitfalls but emphasizes that his views are unprepared, authentic statements of his views and that he will thus carry out his promises to protect his audience. He responds aggressively to every attack, no matter how minor, conveying the sense that he will also aggressively protect his voters.

All this explains why the prior Republican attacks on Trump’s positions and style have gone nowhere. It is not because he is a Teflon candidate. It is because, to his voters, these attacks have stressed what, to them, is Trump’s strength.

The recent Rubio-led attacks on Trump have been more telling because their nature is different. These new attacks say, Trump is a con artist who will not protect you because he defrauded students at Trump University and hired foreigners over American workers. These attacks resonate more than prior attacks because they undermine Trump’s core claim that he will protect his voters.

However, the Super Tuesday results indicate that these attacks have, so far, been ineffective. The likely reason is that, even if these attacks create doubts about whether Trump will follow through on promises to protect his voters, he remains the Republican candidate who at least says he values protecting them over adhering to ideology.

To win over these voters, Trump’s opponents have to go beyond such attacks. They have to affirmatively explain just how they will protect the interests of Trump’s voters better than Trump would. They need to do something dramatic to emphasize their independence from moneyed interests, like vowing to use public financing in the general election and to seek the override of opinions like Citizens United. They need to lay out in detail how they are going to protect jobs, retirement benefits, and health care for the working class, rather than expecting voters to trust that adherence to Republican ideology will do so. They need to express military policies that are sensitive to protecting not only Americans’ security at home but also the lives of American soldiers abroad.

They also need to stress that protection through a strong man has a dark side. Here, Trump has given them plenty of ammunition, like his suggestion that he would like to change constitutional law so he could use libel laws to suppress critique. Voters who crave protection must be directly confronted with a new question: If you empower a strong man to protect you, who is going to protect you from the protector?