Key ally threatens to derail summit over Trump's 'unreasonable' demands

Spain's Prime Minister Pedro Sanchez said it is "unreasonable" for some NATO countries to meet U.S. President Donald Trump's demands that they increase their defense spending to 5% of GDP, comments that could derail an international summit intended to appease the American president.

Sanchez's comments come about one week before NATO allies are scheduled to meet in The Hague to discuss American support for its European allies. Trump has previously said he won't protect NATO countries that don't spend at least 5% of their GDP on defense, even though the NATO constitution requires collective defense of countries when they are attacked.

The only time NATO's collective defense provisions have been invoked is following the Sept. 11 attacks.

“The empirical reality is that, for Spain, as for other Nato countries, reaching [5%] defence spending will be impossible unless it comes at the cost of increasing taxes on the middle class, cutting public services and social benefits for their citizens," Sanchez wrote in a letter to Trump that was obtained by The Financial Times.

Trump has tried to get NATO countries to increase their defense spending since his first term. Multiple countries have increased their spending, but Spain has not yet reached the previous goal of spending 2% of its GDP on defense.

NATO Secretary General Mark Rutte has called on NATO countries to increase their defense spending to 3.5% by 2030, including spending at least 1.5% of GDP in adjacent areas like cybersecurity, roads, and bridges. Rutte's plan has received broad support from the alliance, FT reported.

Sanchez is the most prominent left-wing leader in Europe to push back against Trump's defense spending demands. Some right-wing governments have already begun cutting social spending to meet the increased defense spending levels.