Last Friday, Donald Trump and Vladimir Putin met in Alaska for a summit that was high on pomp and pageantry and low on diplomatic breakthroughs in the push to end the Russia-Ukraine war.

On Monday, six European leaders rushed to Washington DC to meet with Trump and assess the consequences of that Putin meeting. While the gathering at the White House was historic, it too was heavy on rhetoric and light on tangible progress.

With little to show from two summits, pressure is intensifying on a president who made ending foreign wars a key campaign promise. But there were two potentially significant developments.

In Monday's White House confab, Trump appeared open to providing US security guarantees for Ukraine if a deal is struck. That is viewed by the Ukrainians, and their European allies, as an essential component in reaching a durable peace.

On Tuesday morning, Trump hedged a bit, saying a US commitment might entail "air support" rather than American soldiers in Ukraine and that Europe would have to shoulder most of the burden.