‘Espouse’ implies an active and public backing of an idea, not just silent agreement. Activists espouse environmental protection vehemently.
Pro Tip 2/3
Positive Connotation
Using 'espouse' suggests a positive and honorable support for something generally seen as good or progressive. She espoused human rights reforms in her speech.
Pro Tip 3/3
Formal Context
‘Espouse’ is more formal; you'll find it in written texts more than in everyday conversation. In our manifesto, we espouse equal opportunities for all.