Sixtieth anniversaries are usually times for great celebration, especially for those commemorating a relationship. Traditionally, husbands buy diamonds for their wives, and the extended family comes together to mark the occasion.

No one should expect any diamonds when European and North American leaders meet at the NATO summit in Strasbourg/Kehl in April, which will celebrate 60 years of the Atlantic alliance. But Europeans do look forward to meeting their new partner, US President Barack Obama.

Unfinished business? Afghanistan may be the Obama administration’s “top overseas military priority” but many Europeans are not persuaded. Photograph: Reuters

President Obama has inherited a much improved political atmosphere at NATO. The 2007 announcement by French President Nicolas Sarkozy that he intended to reintegrate France into NATO military structures – from which it withdrew under President de Gaulle in 1966 – was very well received in Washington. So much so that during 2008 the Bush administration declared its support for a strong EU defence policy, reversing its earlier hostility to that project.

These two diplomatic manoeuvres have removed much of the Franco-American tension that bedevilled NATO politics over the last decade. All this, along with the election of President Obama, would suggest a fresh start for transatlantic relations, and especially for NATO.

Not quite. Despite more upbeat tones in the mood music, the Atlantic alliance still faces many serious challenges, and some profound questions about its future. NATO leaders do plan to start rewriting their strategic concept (see next article), outlining and updating the purpose of the alliance. But a cursory glance at the summit agenda would probably highlight issues such as Afghanistan, Russia, and NATO-EU cooperation (amongst others). None of these subjects are easy, nor do all the allies agree on how to proceed on any of them.

Take Afghanistan, which Robert Gates, the US defence secretary, has said the Obama administration regards as its “top overseas military priority”. Not all Europeans would concur with that assessment. When President Obama visited Berlin last year (as the Democratic Party’s presidential candidate) some 200,000 gathered to hear him speak.