WHEN THE Democratic Party’s fourth primary debate got under way in Westerville, Ohio, on October 15th, it quickly became clear that the presidential race had changed. Instead of attacking Joe Biden, the former vice-president and front-runner in the race, as they had in previous contests, the candidates turned much of their fire on Elizabeth Warren, a senator from Massachusetts. According to The Economist’s latest polling figures, Ms Warren is now tied with Mr Biden for first place, having briefly led the Democratic field earlier this month. Her steady ascent shows little sign of stopping.

Her support comes from several important demographic groups among Democratic primary voters. According to YouGov, a pollster, 35% of self-described liberals now consider her their first choice to be their party’s nominee for president. Another 16% of moderates and 6% of conservatives also say she is their top pick. Ms Warren has won over 32% of white voters, 15% of black voters and 18% of Hispanics. Even white voters without a college education now favour the professorial Ms Warren over her rivals. Of these voters, 27% say they would opt for her, compared with 22% for Mr Biden and 18% for Bernie Sanders, a senator from Vermont. That could put Ms Warren in a strong position to draw away part of Donald Trump’s core support.

Ms Warren generates enthusiasm among her followers. But her popularity among supporters of her rivals in the Democratic field is even more impressive. A large proportion of Democrats who favour the other leading contenders would consider voting for Ms Warren, including 41% of Mr Biden’s supporters and 40% of Mr Sanders’ boosters. A whopping 52% of those who favour Pete Buttigieg, the mayor of South Bend, Indiana, would consider Ms Warren, too. Among the leading candidates, only supporters of Andrew Yang, an entrepreneur from New York, do not rank Ms Warren as their second choice.

Thus far in the race, only a handful of relatively unknown candidates have dropped out (the latest, Tim Ryan, a representative from Ohio, had been polling at less than 1%). Once the better-known contenders start to fall, it will be Ms Warren who stands to gain most.