They wanted a pretext for subduing the region by force. [+ for]

他们想找借口用武力征服这个地区。

He excused himself on the pretext of a stomach upset.

他借口自己胃不舒服离开了。

They would now find some dubious pretext to restart the war.

他们现在会找个蹩脚的借口重新发动战争。