In a wide ranging speech, Anthony Gardner said in considering the EU's often-criticised communication skills he was reminded of comments made by former US President Barack Obama last year.
Gardner said, "It was a terrific speech, but there was only one problem: it should have been delivered by a European politician, not by the President of the United States."
Gardner, US ambassador to the EU from 2014 to 2017, said, "No European politician is giving speeches like that. Unfortunately, we no longer have a president in the United States giving speeches like that either."
He added, "In October last year Secretary of State John Kerry visited Brussels to deliver another speech on the transatlantic relationship to which I also contributed. It was a great speech, but there was a problem: it should have been given by a European politician, not by the US Secretary of State."
Gardner, now a visiting fellow at the College of Europe in Bruges, added, "I have been struck at the defensiveness of many speeches given by national and EU officials. These speeches are full of defensive words that emphasise protection from threats and change.
"I can understand that officials need to demonstrate to their citizens that they are attuned to their fears - about terrorism, uncontrolled migration and a fast-changing environment that includes technological shifts and global competition that have a particularly severe impact on the unskilled."
Gardner said, "But Europe cannot inspire a sense of solidarity with a defensive narrative; it needs to offer a vision that can inspire."
The experienced diplomat was speaking on the topic of how Europe should communicate its purpose and how the EU institutions should communicate their contribution to improving the lives of ordinary citizens.
Gardner said, "Europeans tend to mock the State of the Union speeches delivered by US presidents because they seem naïve, overly optimistic and perhaps jingoistic."
But, he noted, "Many member states consider the EU, and talk about the EU, as if it were some external alien force that does things (usually negative) to the member states."
This has "significant practical consequences because a member state that does not consider itself a shareholder won't invest in the common enterprise with the hope of eventually extracting dividends."
He went on, "The simple fact undermines the ability of Europe to communicate to its citizens the importance of the European project."
Gardner, who four months after he left office has still has not been replaced as US ambassador to the EU, said, "I am repeatedly struck at how often European politicians resort to the game of blaming Brussels for everything that is hard or wrong.
"Some other member states seem to be at pains to undermine consensus at the EU level and to vilify the EU as an undemocratic body governed by Berlin.
"The lack of European solidarity and Brussels bashing is nothing new, of course; it has been going on for decades; but the accumulated effects of it are severe."
Gardner said EU leaders "are only slowly beginning to recognise that the strategy can backfire."
He cited former UK Prime Minister David Cameron as an example, saying, "He recognised this too late. For years he had repeatedly denigrated the European Union in order to appease the eurosceptics in his party.
"A short time before the Brexit referendum, Cameron underwent a dramatic conversion, like Saint Paul on his way to Damascus: he urged the UK public during the Brexit referendum to consider the EU as a critical motor of prosperity and a provider of security in uncertain times. It was no surprise that few were convinced."
Gardner, an ardent supporter of the EU, said, "The lesson is clear: if member state leaders perpetually denigrate the European project in the eyes of European citizens, the feeling of solidarity - the essential glue that keeps the project together - is at risk of evaporating."
Communicating Europe, even to its own citizens, was "never going to be an easy task," but Gardner said, "I am convinced that Europe can make a stronger case."