power grab       
noun [ C ] uk/ˈpaʊə ˌɡræb/ us/ˈpaʊ.ɚ ˌɡræb/
 夺权
an occasion when a person or group takes advantage of a situation in order to take control
  There have been no labour union power grabs. 没有发生过工会夺权的情况。 
 Critics call the move a power grab and a step backwards for democracy. 批评人士称此举是对权力的攫取,是民主的倒退。 
 - More examples
 - He's facing a power grab by former warlords in parliament.
 - This is not the time for power grabs, bickering, or any divisiveness.
 - They claim that the states are victims of a federal power grab by leaders in Washington.