Their policies on Syria, Russia, terrorism and the European Union.
Will recent photos of chemical attack victims in Syria provoke a short-term emotional reaction or a sustained humanitarian campaign?
The future of the relationship between the US and Russia depends on whether the Kremlin can find a way to interpret Trump's motives.
What vastly complicates Western policy in Syria is how to sanction Assad on one hand and deal with Islamic State on the other, without the country unravelling completely.
To understand the complexities of the conflict in Syria and what might happen next, it helps to untangle the three layers of strife in the war-torn country.
The West's chosen solution to the Syrian conflict demands action that it's unwilling to take.
Christian calendars usually differ when it comes to Easter celebrations – but not in 2017.
The Organisation for the Prohibition of Chemical Weapons Fact Finding Team has not yet revealed the nature of the chemicals used in Khan Sheikhoun.
Scientists invented chemical weapons; some are now working to destroy them. New biomolecular design techniques let researchers design proteins that can destroy nerve agents in bodies.
Trump's attack on Assad's air force was opportunist and reckless. It was also long overdue.
History suggests it would be a big mistake.
Are Trump’s missile strikes against Syria constitutional? An expert on Congress and foreign policy provides a brief history of how the separation of war powers has blurred over time.
Was this a one-off intervention – or a sign that Trump will undertake more of an effort to undermine the Assad regime?
'America First' apparently doesn't mean a step away from playing the world's policeman – and three more things to note about U.S. airstrikes on Syria.
A thawing of tensions between the two superpowers seems as far away as it was under Obama.
Donald Trump suddenly appears to have been overcome with a sense of responsibility towards the people of Syria. How can that be explained?
The question now is how recent critical changes will impact on-the-ground military strategy.
The US military's attack on a Syrian airforce base sets a worrying precedent of brashness and uncertainty in how the Trump administration may handle future crises in international relations.
A former US diplomat explains why some programs may make sense to cut, while others are crucial to America's moral standing.
Employing Syrian refugees is not the same as protecting them.