The US State Department has just approved the sale of US$2.2 billion of arms to Taiwan – the fourth and largest sale under the administration of President Donald Trump. It has drawn the usual rebuke from Beijing over violation of the one-China principle. But what sets it apart and gets the attention of analysts is the biggest item – 108 Abrams tanks actually requested by Taiwan. Expensive arms purchases invite tactical and strategic scrutiny. Battle tanks confound it when analysts say the island has a greater need for the latest F-16 fighter jets to fend off military threats from Beijing, given that the People’s Liberation Army’s potential deployment of air, missile and naval forces would limit the effectiveness of tanks. The tanks, considered state of the art, would be a badly needed update of the mostly obsolete existing fleet, but they would have little practical military use should there be a conflict with the mainland, which would involve missiles and air power rather than ground forces. Moreover, they are of the heaviest type and not of much use to Taiwan’s mountainous terrain. As a result, many observers see the deal as more symbolic than anything, although it also includes 250 Stinger missiles and related equipment. Bigger deals involving fighter jets were struck under the Barack Obama and George W. Bush administrations. However, with just six months to go to Taiwan’s presidential election, at which the independence-minded Tsai Ing-wen of the Democratic Progressive Party is seeking another term, Beijing must be more sensitive than usual about any arms deal, which would boost Tsai’s standing with her party’s traditional supporters. Indeed, China has demanded immediate reversal of the approval while the United States said the deal did not alter the basic regional military balance. A request from Taiwan in March to buy 66 of the new supersonic F-16 Viper jets to upgrade the island’s existing fleet remains under review, and Trump still has the power of veto over the latest arms deal. Known for tending to be relatively cautious on foreign policy, he may keep his options open to avoid jeopardising the latest truce in the trade war with China, or even to strengthen the American bargaining position.