Joe Biden
Joe Biden

Joe Biden has expanded his lead over the Democratic field in a new CNN poll conducted by SSRS, with 29% of Democratic and Democratic-leaning registered voters saying they support the former vice president.

That’s up to 7 points compared to a CNN poll in late June. No other candidate has made significant gains during that time.

The change returns Biden to a double-digit lead over his closest competitors, Vermont Sen. Bernie Sanders with 15% and Massachusetts Sen. Elizabeth Warren with 14%. Their support hasn’t changed since the beginning of this summer.

In addition to the Biden increase, the only statistically significant change in candidate rankings is a 12-point decrease in support for California Senator Kamala Harris, who got 17% support in the June poll, but now has the 5% backing up potential Democratic voters. That’s similar to the level of support he had in the spring before a sudden increase after his initial debate performance.

CNN’s June poll was conducted in the days immediately following the first round of debates sanctioned by the Democratic National Committee among presidential candidates. Biden’s performance in that debate was widely criticized, while Harris had a highlight challenging him for his views on school bus integration. Biden’s numbers have since recovered in other polls as well, and Harris’s have returned to roughly where they were before the debate.

Joe Biden’s lead grows, Kamala Harris falls

CNN poll conducted by SSRS,
CNN poll conducted by SSRS,

Biden’s lead in poll is bolstered by increased support from self-identified Democrats (31%) than independents (23%), older voters (34% among those over 45) than younger voters (23% among under-45s) and moderate and conservative voters (34%) liberals (22%).

Among the liberals, in fact, the race is almost a draw: 23% choose Warren and 22% choose Biden and Sanders. No other candidate reaches 5% among this group.

Biden is also reinforced by voters who say their top priority is to choose a candidate with a high chance of beating President Donald Trump, a group that represents 54% of Democratic and Democratic-leaning registered voters (the 35% in that group support Biden). That group has shrunk slightly since June, when 61 percent said that defeating Trump outnumbered a candidate who “shares their positions on important issues.”

While Democrats don’t seem to be abruptly divided on this issue by ideology (53 percent of liberals and 57 percent of moderate or conservative Democratic voters say beating Trump is more important), race (54% between whites and non-whites prioritise beating Trump) or partisanship (52% of self-identified Democrats prioritize beating Trump as well as 59% of Independents who lean toward Democrats), there are notable divisions by age and education among whites, which highlights the challenge that candidates face when trying to attract those on both sides of this line.

Among under-45s, 56 percent say it’s more important to nominate a candidate who shares their positions on issues, while 66 percent of over-45s say it’s more important to nominate someone who can defeat Trump. Among whites without college degrees, 49% say it’s more important to nominate someone who shares their opinion on the problems, while 45 percent say beating Trump is more important, but among whites with a college degree, 65 percent say it’s more importantly to defeat Trump.

The survey, which is among those used by the DNC to determine which candidates will qualify for the debate stage in September, marks the fourth rating poll in which former HUD Secretary Julián Castro has reached 2%, securing his place on stage in Houston next month.

Castro is the tenth candidate to qualify for a position. Two other candidates say they have already reached the fundraising threshold to appear on stage in September, but have yet to reach the voting target: entrepreneur Tom Steyer follows a rating poll and Hawaii representative Tulsi Gabbard, now has two after reaching 2% in this poll She needs two more to do the debate stage.

New York Senator Kirsten Gillibrand has reached 2% in a rating poll and is the only other active candidate to have reached that mark in any rating poll, but has not met the fundraising criteria.

When asked which candidates they would like to hear the most, Democratic and Democratic-leaning registered voters focus primarily on the people who will appear at the September debate stage.

The 10 candidates named by 5% or more of respondents have now qualified for inclusion in the debates. Warren now tops this list, named at 20%, despite a slight decline in interest to hear more about it compared to June. It follows Harris at 18%, Sanders at 16%, Biden at 15%, Buttigieg at 13%, Booker and O’Rourke at 10% each, Yang at 6%, and Castro and Klobuchar at 5%.

The CNN poll was conducted by SSRS august 15-18 among a random national sample of 1,001 adults contacted on a landline or cell phone by a live interviewer. The results for the full sample have a sampling margin of error of about 3.7 percentage points, for the subsample of 402 Democrats and Democratic-trending independents who are registered to vote, is 6.1 points.