WASHINGTON — Russia could be forced to end the war in Ukraine because it will run out of money to pay its troops, according to experts at the DC-based Institute for the Study of War. The country has burned through roughly half of its $106 billion liquid sovereign-wealth fund, which is used to pay troops’ salaries and new recruits bonuses, experts said. Moscow can likely only afford another 12 to 16 months of fighting at its current pace, with about 30,000 to 45,000 Russian troops killed or injured in Ukraine each month since its 2022 invasion began, ISW’s Russia team...