We’re still reeling from what happened on Sunday in Orlando. Another terrorist attack–not overseas, but here at home. Dozens of Americans killed and wounded. A hate crime at an LGBT nightclub, right in the middle of Pride Month. The deadliest mass shooting in the history of the United States.

Since Sunday, we’ve been trying to make sense of what happened and what we can do together to prevent future attacks. Yesterday in Cleveland, I once again laid out a plan for defeating ISIS and the broader radical jihadist movement — around the world and online — and for combating radicalization here at home, including detecting and preventing “lone wolf” attacks like we saw in Orlando and San Bernardino. These attacks are carried out by individuals who may or may not have direct contact with an organization like ISIS but are inspired by its twisted ideology.

We have to work with Muslim communities here at home, who are often the most likely to recognize radicalization before it’s too late. And, as I’ve said from the very beginning of this campaign, I believe we Americans are capable of protecting Second Amendment rights while making sure guns don’t fall into the wrong hands. The terrorist in Orlando was the definition of “the wrong hands.” And weapons of war have no place in our streets.

The questions about how we deal with the threat of terrorism are some of the most charged and important issues we face, and there are bound to be differences of opinion.

But I believe with all my heart that despite those differences, on a deeper level, we’re all on the same team. That’s what we’re seeing in Orlando and across America — people of different faiths, backgrounds, sexual orientations, and gender identities coming together to say with one voice, we won’t let hate defeat us. If even the families of the Orlando victims are speaking out right now against hate and division, we should certainly expect it from our leaders.

I’m sorry to say that’s not what we’re seeing from Donald Trump.

This man wants to be our next Commander-in-Chief, a job that demands a calm, collected, and dignified response to these kinds of events. Instead, yesterday morning — just one day after the Orlando massacre — he went on TV and suggested that President Obama is on the side of the terrorists.

Even in a time of divided politics, this is beyond the pale. And I have to ask — will responsible Republican leaders stand up to their presumptive nominee? Or will they stand by his accusation about our president?

I’m sure they’d rather avoid that question altogether. But history will remember what we do in this moment.

What Trump is saying is shameful. And it’s disrespectful to the people who were killed and wounded in Orlando and to their families.

Of course, this is a leader of the birther movement, which spread the lie that President Obama wasn’t born in the United States. But it was one thing when he was a reality TV personality — it’s another when he’s the Republican Party’s presumptive nominee for president.

Americans don’t need conspiracy theories and pathological self-congratulations — we need leadership, common sense, and concrete plans. The barbarity we face from radical jihadists is profound, and Americans deserve a worthy debate on the best way to keep our country safe.

I read every word of Trump’s speech yesterday. I sifted through all the bizarre rants and outright lies. And what I found is, once you cut through the nonsense, his plan comes down to two things.

First, he’s fixated on the words “radical Islam.” Is Trump suggesting that there are magic words that, once uttered, will stop terrorists from coming after us? From my perspective, it matters what we do, not just what we say. It didn’t matter what we called Bin Laden — it matters that we got Bin Laden.

I’ve clearly said that we face terrorist enemies who use a perverted version of Islam to justify slaughtering innocent people. We have to stop them, and we will. What I won’t do is demonize and declare war on an entire religion.

Now that we’re past the semantic debate, Trump’s going to have to come up with something better. He’s got one other idea — to ban all Muslims from entering our country and to suspend all immigration from large parts of the world. This approach is un-American. It goes against everything we stand for as a country founded on religious freedom.

It’s also dangerous.

First, we rely on partners in Muslim countries to fight terrorists. Second, we need to build trust in Muslim communities here at home to counter radicalization. This makes all of that harder. Third, Trump’s words will be a recruiting tool for ISIS and help increase its ranks. And fourth, he’s turning Americans against Americans, which is exactly what ISIS wants.

In this instance, though, Trump’s words are especially nonsensical. Because the terrorist who carried out this attack wasn’t born in Afghanistan, as Trump said yesterday. He was born in Queens — just like Donald Trump. Muslim bans and immigration reforms wouldn’t have stopped him, and they wouldn’t have saved a single life in Orlando.

Those are the only two ideas Trump put forward yesterday for how to fight ISIS. Beyond that, he said a lot of false things about me. He said I’ll abolish the Second Amendment. Wrong. He said I’ll let a flood of refugees into our country without any screening. Also wrong.

These are demonstrably lies. But he feels compelled to tell them — because he has to distract from the fact that he has nothing substantive to say for himself.

Trump has been very clear about what he won’t do: He won’t stand up to the gun lobby.

The terrorist who killed 49 people and wounded 53 others in Orlando did it with two guns: a handgun and a Sig Sauer MCX rifle. This man had been investigated by the FBI for months, but we couldn’t stop him from buying a powerful weapon he used to slaughter Americans in large numbers.

We’ve reached the point where people can’t board planes with full bottles of shampoo — but people being watched by the FBI for suspected terrorist links can buy a gun with no questions asked. If you’re too dangerous to get on a plane, you’re too dangerous to buy a gun.

Enough is enough. Now is the time for seriousness and resolve.

We need to go after ISIS overseas, protect Americans here at home, counter poisonous ideologies, support our first responders, and take a hard look at our gun laws — and we need to stand with LGBT Americans and peaceful Muslim Americans, today and always.

America is a big-hearted, fair-minded country. We teach our children that this is one nation under God, indivisible, with liberty and justice for all. Not just for people who look a certain way, or love a certain way, or worship a certain way — for all.

That fundamental American ideal is why I’m so confident that we can overcome the threats we face. We can solve our challenges at home. And we can build a future where no one’s left out or left behind. Because we’re stronger together.