Obama in Europe, Ukraine issue at top of agenda

President Obama's trip to Europe had been planned, but the timing was important for the situation in Ukraine. This overview in the Washington Post's Wonkblog lays out the critical issues going forward:

Wonkbook: How the crisis in Ukraine is shaking up Obama’s trip to Europe

Obama emphasized unity between the U.S. and Europe, although differences remain, particularly on the issue of military spending.

Obama: U.S. and Europe united over Ukraine crisis

Despite ‘wake-up call’ in Ukraine, Europe reluctant to bolster its militaries

The sanctions regime will take time to impact Russia, as explained by former LBJ faculty member James Lindsay:

What U.S. sanctions against Russia will (really) do

In the latest news, Secretary of State John Kerry is returning earlier than planned to Europe, to explore new prospects for diplomacy...

John Kerry Changes Course On Overseas Trip, Stays In Europe For Ukraine Talks

Ukraine highlights the dangers ahead for the EU:

Ukraine Upheaval Highlights E.U.’s Past Miscalculations and Future Dangers

Ukraine - Background and Developments up through the referendum in Crimea, March 16, 2014

Timeline of developments in Ukraine since it declared independence from Russia in 1991

BBC Ukraine Timeline

Some links with streaming updates:

Wall Street Journal Streaming News on Ukraine

Yannis Koutsomitis Storify: Ukraine after Regime Change

CNN: Crisis in Ukraine

The referendum on Crimea took place today with the expected outcome of the referendum in Crimea:

BBC on the Referendum in Crimea

The Ukrainian Prime Minister sent a warning to Russian separatists and the outcome of the referendum could lead to a loss of resources for Crimea - and a painful switch over to dependence on Russia:

Ukraine Prime Minister sends warning to Pro-Russian separatists

Meanwhile in Moscow, thousands protested, including members of Pussy Riot:

Tens of Thousands Protest Putin

From the White House: