The United States on Wednesday implored Sudan’s authorities to let aid into the country, denouncing holdups as the war between rival generals leaves millions in need of help. Samantha Power, administrator of the US Agency for International Development, said that funding for Sudan’s crisis “remains shockingly low,” with around 25 million people, or more than half of the population, in need of assistance. But she said that even the aid that arrives faces obstacles due to “ill-disciplined or rapacious” forces on the ground, and bureaucracy “mastered through decades of practice at being obstructio…