US President George W. Bush waves with Slovenian Prime Minister Janez Jansa at his arrival in Ljubljana airport on June 9, 2008. Bush arrived in Slovenia on Monday for his farewell US-European Union summit at the start of a week-long tour of the continent. [Agencies]

President Bush has arrived in Slovenia to begin a weeklong tour through Berlin, Rome, Paris and London. It appears every bit the glamorous old-style farewell tour with a leisurely schedule, jaunts to country castles and lavish dinners.

But it's actually a high-stakes diplomatic mission, spurred by Bush's fear that Iran is an increasingly urgent threat and that Europe may not take it seriously enough.

Bush has never been popular in Western Europe after the US invasion of Iraq. "A lot of people like America. They may not sometimes necessarily like the president but they like America," Bush told a reporter from Slovenia.

So it was puzzling that he decided to buzz through all of Western Europe's Big Four nations this week, risking large protests and pointed questions, instead of choosing, as he usually does, to stop in formerly communist, newly democratic Central and Eastern European countries where he always gets rock-star welcomes.