be under the illusion that
Believe mistakenly that: the world is under the illusion that the original painting still hangs in the Winter Palace...- ‘No one should be under the illusion that because a plan exists in one form today that it will be that way forever,’ he said.
- The Popular Unity's supporters were under the illusion that once in power it would fulfil the promise of profound political and socio-economic change.
- Progressives have been under the illusion that if only people understood the facts, we'd be fine.
See parent entry: illusion