Japan is bracing for a more unpredictable ally in Washington, as the US midterm elections threaten to deepen political gridlock and complicate Tokyo’s long-term security calculations, analysts say. Observers warn that post-election political battles, ranging from a possible repeat of impeachment proceedings to the mounting legal battles ensnaring the administration of US President Donald Trump, risk diverting the White House’s attention from foreign policy and its long-standing commitments to...