Alexandria Ocasio-Cortez is a rising star in the progressive wing of the Democratic Party — bold, outspoken and hugely popular on social media.

But the millennial congresswoman is reportedly sparking concerns among some top Democrats, with fears her defining presence could lose the party crucial swinging voters at the 2020 election.

The issue has come to a head this week, with Ms Ocasio-Cortez at the centre of a Twitter spat with US President Donald Trump.

Gorana Grgic, an expert at the United States Studies Centre, says on one hand, the popularity of the “squad” only goes so far.

“If you look at the districts that all four of these women are in, they’re solidly blue,” she told “AOC is maybe the only example of beating the old guard of the Democratic Party … but the other three obviously replaced representatives that were going into retirement.