The Mexican peso slumped after U.S. President Donald Trump imposed new import tariffs against the country, though other developing-nation currencies held their own amid concerns about the impact of the escalating trade war on growth in the world’s largest economy. The peso fell as much as 1% against the dollar, extending its decline to a fourth day and hitting the weakest level in a month after the 25% duties came into effect, together with levies on Canada and China. Investors are awaiting Mexico’s response, with President Claudia Sheinbaum expected to...