Voices Carry: How Careless Campaign Bombast Can Undo Administrations - alumna Danielle Luption and Peter Feaver coauthor
Yes, they are, though political scientists have argued for years whether credibility really matters in foreign policy. There is an older body of scholarship that suggests concerns over credibility are overstated (for a sympathetic review of that literature, see here). According to this view, leaders could make idle threats and not pay a price, because in each new contest, the actors discounted heavily whatever had been done or not done, said or not said, in earlier stages.
However, more recent scholarship has debunked the “credibility does not matter” school. For instance, the dissertation one of us (Danielle Lupton) wrote shows that making unrealistic threats and promises that you may not be able or willing to keep in the future is an entirely unwise course of action. Drawing on new archival material, her evidence from the history of U.S. foreign relations during the Cold War, as well as new experimental research, demonstrates that statements create expectations of future behavior. Leaders who make assertive statements and then fail to deliver on their promises can see their reputations seriously damaged and leave their countries more vulnerable to threats from abroad.