Vampire Weekend frontman Ezra Koenig has been left disappointed by U.S. President Barack Obama, admitting he was "naive" to believe the politician could change America.

The New York-based rockers were vocal advocates of the Democrat prior to his election victory in 2008 but they have since felt frustrated by his failure to introduce sweeping changes to the country.

The lack of progress has left the band's singer/guitarist Koenig doubting the wisdom of voting for Obama and made him realise political change often fails to impact on the general populous.

He tells NME magazine, "Things haven't changed in a massive way since Obama was made president. Probably even Obama would agree with that. But that sense of hope people had when he was first elected has dissipated. You realise there's certain things so ingrained into the fabric of how our government works that to expect one man to change that is a little bit naive.

"That makes you feel even worse, because the whole system's predicated on people waiting every four years to pretend that one person is going to change those things. That makes me feel like the whole system's broken. So, on that level, of course there's disillusionment."