You may have heard: President Donald Trump replaced his national security adviser, H.R. McMaster, with John Bolton.

You may have heard because of the mixed reaction to the prospect of Bolton running national security — “mixed” as in apocalyptic among leftists and heaven-sent to many on the right.

Look no further than the pro-Israel spectrum for each extremes:

>> What Bolton pick means for Netanyahu and Iran

“We are horrified by his selection to be national security adviser and believe this move by the president gravely imperils our country’s national standing and the fundamental security of the United States and its allies, including Israel,” said Jeremy Ben-Ami, the president of J Street, the dovish Jewish Middle East policy lobby.

“I have no doubt that the sensitivity and skill that permeates everything he does will be evident to the entire nation in his new role as President Trump’s national security adviser,” said Joseph Frager, the first vice president of the National Council of Young Israel, a hawkish Orthodox group. “Mazel Tov, old friend, on your well-deserved appointment.”

So let’s get out of the way some of the more commonly known stuff that’s fueling this frenzy:

* He hates the Iran nuclear deal. Trump and the centrist and right-wing pro-Israel community also revile the agreement, which swaps sanctions relief for a rollback in Iran’s nuclear program.

“Not only does the entire agreement reflect appeasement, but President Obama’s diplomacy produced weak, ambiguous and confusing language in many specific provisions,” Bolton wrote in a February 2017 Wall Street Journal op-ed. “These drafting failures created huge loopholes, and Iran is now driving its missile and nuclear programs straight through them.”

Naming Bolton suggests that Trump is ready to pull out of the 2015 agreement by May 12, the deadline to waive sanctions.

* He believes preemptive strikes could prove useful in keeping Iran from going nuclear.

“I don’t make any disguise of the idea that ultimately it may take an Israeli strike against Iran’s nuclear program to stop it,” he told the conservative Washington Free Beacon in August.

* He does not believe two states is a Palestinian-Israeli option.

The United States should “advocate for a three-state solution which would merge Gaza with Egypt, and parts of the West Bank with Jordan,” Bolton said last year accepting Bar-Ilan University’s Ingeborg Rennert Center for Jerusalem Studies Guardian of Zion Award.

“I don’t think there is a viable Palestinian state. I don’t think there are institutions on the Palestinian side that can live up to the commitments of a treaty with Israel, that could give Israel or the U.S. or anyone confidence that such a state could provide for the well-being of the Palestinian people or could resist takeover by terrorist elements.”

Trump has said he is agnostic on two states, and Israeli Prime Minister Benjamin Netanyahu has retreated from his backing for the outcome. The Palestinian Authority is still committed to the outcome.

Now let’s get to what you might not know or remember about Bolton:

He still loves the Iraq War

Bolton’s naysayers have been rushing to social media to point out that not only did he back the Iraq War, unlike many of its one-time backers who now say the war was catastrophic (most famously among them Trump), he still believes it was a good idea.

“I still think the decision to overthrow Saddam was correct,” he told the Washington Examiner in 2015. “The people who say, oh things would have been much better if you didn’t overthrow Saddam miss the point that today’s Middle East does not flow totally and unchangeably from the decision to overthrow Saddam alone.”

The Iraq War brought into power in Shi'ite-dominated Iraq a government that facilitated Iran’s expanding influence in the region, as well as created a vacuum elsewhere that was filled to a large degree by the Islamic State and other radical Sunni Muslim terrorist groups.

but it wasn’t his hawkishness that sidelined him in 2006.

In 2005, President George W. Bush named Bolton as acting ambassador to the United Nations after Democrats blocked his confirmation, citing his disdain for the body expressed in 1994.

“The Secretariat building in New York has 38 stories,” he said. “If it lost 10 stories, it wouldn’t make a bit of difference.”

But that’s not what scuttled his bid: Some of his subordinates at the State Department stepped forward to testify that Bolton was a mean boss. One staffer described him as someone who “kissed up and kicked down.” The late Ohio Sen. George Voinovich, a Republican, stunned his colleagues when he sided with the staffers — and declared Bolton unfit.

“I’ve heard enough today that I don’t feel comfortable about voting for Mr. Bolton,” Voinovich said after a Senate Foreign Relations Committee hearing in April 2005. “I think one’s interpersonal skills and their relationship with their fellow man is a very important ingredient in anyone that works for me.”

Bolton’s nomination made it out of committee but, largely because of Voinovich’s distaste for him, never made it out of the Senate. Bolton was a recess appointment, and that lapses once Congress is reseated for a new session. By the end of 2006 he was out.

He is an effective diplomat

However much Bolton might have wanted to lop off a goodly portion of the U.N. building, it appears he was capable of forging alliances there. As the assistant secretary of state for international organization affairs under President George H.W. Bush, he steered the U.N. General Assembly to a vote in 1991 that rescinded its notorious 1975 “Zionism is racism” resolution. Bolton leveraged U.S. economic assistance and the post-Iron Curtain chaos in Europe and the former Soviet Union to pull off a win.

with interesting friends.

Bolton breaks bread with folks that the mainstream Jewish community could do without. He wrote the foreword to “The Post-American Presidency: The Obama Administration’s War on America,” by Pamela Geller and Robert Spencer. The Anti-Defamation League lists Geller as an “anti-Muslim activist” who “not only contradicts the Jewish-American values which she claims to defend but it also violates basic human decency.”

Bolton was annoyed by calls for President Barack Obama to “prove” that he was born in the United States, but it didn’t keep him from catering to those conspiracy theorists with pointed jokes about Obama. Speaking at a 2016 conference that the ADL called a “who’s who of the anti-Muslim movement in the United States,” Bolton joked that Jordan’s King Abdullah (whom Bolton was holding up as a righteous pro-Western Muslim) “is not simply a Muslim king of a Muslim country, unlike our president.”

Worry in the Middle East

Lebanese newspaper al-Akhbar, aligned with the Shi'ite militant group and political movement Hezbollah, reported Bolton's appointment with the headline "Zionist Hawk in the White House", drawing attention to Bolton's historical calls for action against Iran.

"Bolton's appointment, combined with (Mike) Pompeo's nomination (for secretary of state) last week, significantly lowers the odds that Trump will stick to the nuclear deal beyond May," said Ellie Geranmayeh, senior policy fellow at the European Council of Foreign Relations.

"Both men have vocally opposed the nuclear deal, advocated for regime change in Iran and Bolton has repeatedly called for bombing rather than diplomacy as a fix to the nuclear issue."

Turkey's response to the appointments of Pompeo and Bolton was cautious. "We hope these changes of duty will be a means to further strengthen the continuing efforts to solve the problems that have existed between our countries for a long time," a foreign ministry spokesman said.

He got the pro-Israel community to do something unique.

Pro-Israel groups rarely endorse a nominee who needs Senate confirmation: There’s no point in alienating the other party, the thinking goes. And the American Israel Public Affairs Committee never does.

Bolton’s role in undoing the Zionism is racism resolution made him perhaps the most outstanding exception to that rule. In addition to AIPAC, groups that lobbied in 2006 for his confirmation as U.N. ambassador included the American Jewish Committee, the Anti-Defamation League, the Orthodox Union, Agudath Israel of America, the Zionist Organization of America and the Republican Jewish Coalition.

The Conference of Presidents of Major American Jewish Organizations quietly encouraged the endorsements. “John Bolton is an important and very effective representative of the United States at the United Nations and has consistently been a strong advocate for the U.S. on issues that matter to the pro-Israel community,” Josh Block, AIPAC’s spokesman at the time, said.

Don’t call him neoconservative.

Bolton, because of his arduous Iraq War backing, is often lumped in with neoconservatives. He’s not. He believes in intervention when what he sees as U.S. interests are threatened — but he doesn’t want to stick around to promote democracy and nation-build, preferring to hand off running the country to friendly dictators, if need be.

“He has little interest in exporting democracy or human rights or in restructuring other societies,” a contributing editor to Foreign Policy magazine wrote on Twitter. “He supported the Iraq War, but his preference was to withdraw soon after Saddam was ousted rather than engage in nation-building.”

He differs with Trump on Russia

Trump of late is picking folks he likes on TV — Fox News Channel, particularly, where Bolton is a contributor — to help him run the country. Bolton’s pronouncements on North Korea (meet with its leader, but maintain a credible threat of a military strike) and Iran (kill the deal) have pleased Trump.

But Bolton, if he was angling for the White House job, has not been shy about differing with Trump, who counsels friendliness to Russia. Trump has not yet used sanctions at his disposal to target Russia for its meddling in the U.S. elections and its mischief-making elsewhere. Bolton believes the Trump administration should do more.

“If you want to punish a country for behavior you don’t accept, you need punishing sanctions that are broad, not targeted, and they need to be enforced,” Bolton said in a recent tweet.

but he’ll defer to the boss.

Bolton had an appearance scheduled Thursday evening on Fox News when he learned Trump had released the news. The Fox interviewer put him on the spot about differences with Trump on Russia.

“I’ve never been shy about what my views are but frankly, what I’ve said in private now is behind me, at least effective April the 9th, and the important thing is what the president says and what advice I give him,” he said.

Reuters contributed to this report