Before the start of business, Just Security provides a curated summary of up-to-the-minute developments at home and abroad. Here’s today’s news.

SYRIA

A suspected Syrian government gas attack in Idlib province crossed “many, many lines” and was “a terrible affront to humanity,” President Trump said yesterday, signaling a more aggressive policy toward Syria than he previously indicated, though he did not elaborate on what his response would be, Carol E. Lee, Dion Nissenbaum and Farnaz Fassihi report at the Wall Street Journal.

The US might take unilateral action if the Security Council fails to respond to the chemical attack, UN ambassador Nikki Haley warned yesterday, also roundly blaming Russia for blocking a strong UN response. Somini Sengupta and Rick Gladstone report at the New York Times.

The US government needs to rethink its support for Syrian President Bashar al-Assad, Secretary of State Rex Tillerson said yesterday, Olivia Beavers reporting at the Hill.

“All options are on the table” with the US’ response to the chemical attack, Vice President Mike Pence explained yesterday, laying the blame for the attack on Assad. Cristiano Lima reports at POLITICO.

There is “no option except victory” in Syria and his government could not reach “results” with opposition groups at the recent peace talks, Assad said in an interview published today. [Reuters]

Differences with Washington over the use of chemical weapons in Syria are not likely to worsen US-Russia ties, the Kremlin said today. [AP]

The volatility of the Trump administration is demonstrated by the president’s declared change of stance on the chemical attack, his suggestion that the US might intervene militarily in Syria a major departure from the “America first” policy that has defined his approach up to now, write Julian Borger and Spencer Ackerman at the Guardian.

The White House was aware that Assad was gassing his people but chose to ignore it. That was the subtext to President Trump’s message yesterday when he disclosed that the White House was aware of a series of chlorine attacks leading up to this week’s deadly suspected sarin strike, write Kimberly Dozier, Roy Gutman and Noah Shachtman at The Daily Beast.

Trump’s comments yesterday were are start, but what will he do? Commander-in-chief Trump must decide whether to continue the US’ passive approach to Syria embodied by his predecessor or to chart a new course, writes Jennifer Rubin at the Washington Post.

Trump must back up his words with action, agrees Paul Wolfowitz at the Wall Street Journal, and reassess recent statements by members of his administration indicating that US does not prioritize removing Assad from power, statements which may have signified to the dictator that he could continue to terrorize the Syrian people.

Autopsies conducted on victims of the attack by Turkish doctors confirm that chemical weapons were used, Louisa Loveluck reports at the Washington Post.

Evidence points to nerve gas exposure, US intelligence officials, Doctors Without Borders and the UN health agency said yesterday, while the UN Security Council argued over whether to hold Assad’s government responsible for Tuesday’s attack which left more than 80 dead. Philip Issa and Sarah El Deeb report at the AP.

Soil samples from the scene of the attack were gathered and set to western intelligence officials to try to determine specifically what nerve agent was used, Martin Chulov reports at the Guardian.

Resume peace talks and prosecute Assad’s government over its alleged use of chemical weapons rather than rush into new military intervention, France’s foreign minister urged this morning, the AP reporting.

The Obama administration’s “so-called red lines,” which should have triggered a military intervention in Syria if crossed, are to blame for Assad’s progression from using toxic chemicals to “full-blown poisonous substances,” Russia’s deputy permanent representative to the UN Vladimir Safronkov told the UN Security Council yesterday. [TASS]

The chemical attack was an elaborate playact, Russian foreign ministry spokesperson Maria Zakharova intimated yesterday, despite a US-EU assessment and reflecting her predecessor Alexander Lukashevich’s comments in relation to the massacre in Ghouta in 2013, Michael Weiss writes at The Daily Beast.

What does the evidence tell us about the reliability of Russia’s account of the attacks? Jeffrey Marcus explains at the New York Times.

Russia must not stand by as its emboldened surrogate the Assad regime gasses civilians, in blatant contravention of an agreement to which Russia is the guarantor, writes the Financial Times.

The history of Assad’s use of chemical weapons and other atrocities is examined by Russell Goldman at the New York Times.

The TRUMP ADMINISTRATION

Steve Bannon was removed from the National Security Council’s principals committee yesterday, a shift orchestrated by President Trump’s national security adviser Lt. Gen. H. R. McMaster and carried through by the President despite Bannon’s resistance, Peter Baker, Maggie Haberman and Glenn Thrush write at the New York Times.

A presidential memo dated April 4 removes Bannon from the US’s main body for foreign policy and national security decision-making and restores the traditional roles of the chairman and joint chiefs of staff and the director of national intelligence to the NSC, explains Spencer Ackerman at the Guardian.

UN Ambassador Nikki Haley and Energy Secretary Rick Perry are slated to join the NSC principals committee as part of the rearrangement, Mallory Shelbourne reports at the Hill.

Does Bannon’s removal – and national security adviser K. T. McFarland’s probable exile to Singapore – mean that national security adviser McMaster has won? Not so fast, writes Jonathan Stevenson, highlighting other signs that Trump’s national security team is still as weak and dysfunctional as ever at the New York Times.

Former New Mexico Republican Rep. Heather Wilson was approved to serve as secretary of the Air Force by the Senate Armed Services Committee yesterday, Ellen Mitchell reports at the Hill.

TRUMP’S WIRETAP CLAIMS

Former Obama national security adviser Susan Rice may have committed a crime in requesting the identities of Trump campaign associates in classified intelligence reports, President Trump told the New York Times’ Maggie Haberman, Matthew Rosenberg and Glenn Thrush, offering no evidence to support his claim.

Declassify the surveillance documents showing that Susan Rice broke the law, Rep. Eric Swalwell (D-Calif.), on the House panel investigating Trump’s ties to Russia, challenged the President yesterday, Austin Wright reporting at POLITICO.

TRUMP CABINET RELATIONSHIP WITH RUSSIA

House Intelligence Committee Republicans boycotted a briefing on Russia intelligence methods organized by Democrat Rep. Eric Swalwell for yesterday with the intention that the committee could meet in a bipartisan manner to hear non-controversial testimony, Tim Mak at The Daily Beast citing it as the latest example of the “dysfunction, partisanship, and paralysis” that has been a feature of the panel since its chairman’s actions stalled its investigation.

The Logan Act’s true history should worry the Trump administration. While it’s true that no one has been convicted of violating the Logan Act since it was signed over 200 years ago, what those who say the law is defunct miss is the fact that it has been “enforced” and relied on repeatedly by the executive branch, especially through the State Department. Just Security’s co-editor-in-chief Ryan Goodman explains at the Washington Post.

TRUMP-XI MEETING

Taiwan is confident that its relations with the US will not be harmed when President Trump holds his first summit with his Chinese counterpart today, Taiwan said today, citing reassurances from the US. [AP]

Five issues stoking US-China tensions to look out for at the Trump-Xi summit today and tomorrow, including North Korea, Taiwan and the South China Sea, are identified by Demetri Sevastopulo and Tom Mitchell at the Financial Times.

The danger is that Trump, improvising, will be drawn into Beijing’s conception of a “new form of great power relations” much as Secretary of State Rex Tillerson was when he recently visited China, writes the Washington Post editorial board.

Trump should focus on his administration’s worldview, very different to his predecessor’s, at the Xi summit if he is to make America’s foreign policy great again, suggests John Bolton at the Wall Street Journal.

TRUMP ADMINISTRATION FOREIGN POLICY

President Trump’s early engagement with challenges in the Middle East is “beginning to bring Palestinians and Israeli’s together,” King Adbullah II of Jordan said while standing outside the White House yesterday with President Trump, both leaders promising to work together to find a solution to peace and stability in the region. [Al Jazeera]

Secretary of State Rex Tillerson will meet with Kremlin Foreign Minister Sergey Lavrov and other Russian officials in Moscow next Wednesday, topics of discussion to include Ukraine, North Korea, Syria and counterterrorism, Madeline Conway reports at POLITICO.

The UN Security Council will come to the White House later on April 24 to meet with President Trump and congressional leaders, according to an anonymous diplomat. Edith M. Lederer reports at the AP.

Trump discussed the situations in Ukraine and Afghanistan in a phone call with German Chancellor Angela Merkel yesterday, Reuters reports.

NORTH KOREA

Diplomatic and economic measures taken to try to stop North Korea’s missile program have not worked, a “senior US military commander” said today ahead of the President’s meeting with Chinese President Xi Jinping, Tim Kelly and Ju-min Park reporting at Reuters.

Trump discussed North Korea’s latest missile launch with Japanese Prime Minister Shinzo Abe today, the two leaders agreeing to “stay in close communication to enhance cooperation on North Korea,” according to the White House. Olivia Beavers reports at the Hill.

Why doesn’t China do more to rein in North Korea’s ballistic missile program? The Economist explains.

The MUSLIM BAN

Lawyers representing six states trying to permanently block President Trump’s revised travel ban want the government to cooperate if they serve subpoenas on Trump and others, according to a report filed in federal court in Seattle yesterday. The AP reports.

One of President Trump’s main campaign advisers on immigration was ordered to turn over a document he took to a meeting with Trump last November that included proposals for registration of citizens from high-risk countries, extreme vetting on foreign visitors, a ban on Syrian refugees, deporting aliens charged with crimes and building a wall along the border with Mexico by a federal magistrate yesterday, Josh Gerstein reports at POLITICO.

IRAQ

The Iraqi army will slow its offensive on the old district of Mosul in an effort to minimize civilian casualties, meaning fewer US and Iraqi air strikes, the Iraqi commander coordinating the battle to oust the Islamic State from the city told NPR’s Jane Arraf.

US-led airstrikes continue. US and coalition forces carried out 15 airstrikes against Islamic State targets in Syria on Apr. 4. Separately, partner forces conducted 11 strikes against targets in Iraq. [Central Command]

SOUTH CHINA SEA

The Philippines’ military is to occupy and fortify all Philippine-held islands in the disputed South China Sea to assert the country’s claims there, President Duterte said today, Teresa Cerojano reporting at the AP.

Chinese coastguard vessels are maintaining an almost constant presence around reefs claimed by Malaysia in the South China Sea, Oliver Holmes reports at the Guardian.

ST PETERSBURG ATTACK

Seven suspected Islamic State recruiters were rounded up by investigators looking for accomplices of the St. Petersburg suicide bomber, but found no immediate evidence of their involvement in the attack, Irina Titova and Vladimir Isachenkov report at the AP.

An explosive device in a residential building in St. Petersburg was made safe by Russian authorities today in the wake of a deadly bomb attack on the city’s subway Monday, Reuters reports.

OTHER DEVELOPMENTS

A car driven by a Palestinian was deliberately rammed into two Israeli soldiers, killing one, in the occupied West Bank today, according to the Israeli military. [Reuters]

NATO needs to adapt better to combat terrorism and cybersecurity threats, UK Defense Secretary Michael Fallon said yesterday, expressing the hope that President Trump would be convinced about the alliance reforming itself. Jenny Gross and Stephen Fidler report at the Wall Street Journal.

Afghanistan is pointing to its untapped wealth of minerals, including lithium, in an attempt to get the attention of President Trump and gain extra US support, Rahim Raiez writes at the AP.