Americans largely disapprove of the way Hillary Clinton has handled the controversy around her private email address, according to a new Washington Post/ABC News poll that shows the Democratic frontrunner’s support dropping significantly within her party over the two months.

The poll illustrates the challenges the Clinton campaign has faced in controlling the narrative around her use of a private email server during her time as Secretary of State. Some 55% of Americans disapprove of the way Hillary Clinton has handled questions about her use of private email, and 51% say Clinton broke government regulations in her use of private email. Fully 54% say that she tried to cover up the facts.

It’s unclear, however, whether the email issue will persist into 2016 and hurt her if she is chosen to represent the Democrats in the general election: fewer than half of Americans think it is a legitimate issue in the presidential election, according to the poll. And Clinton still holds a commanding lead in the nominating contest: 42% of Democratic-leaning voters support Clinton, compared with 24% supporting second place Bernie Sanders.

But a summer dominated by headlines about the email controversy has impacted her bid for the nomination. Her support among Democrats has dropped 21 points since July.

Clinton did not break any rules by emailing work-related information from a private account, as the rules that restrict that practice were enacted in 2014, after Clinton left the administration. It is illegal to intentionally transmit classified information on unsecured channels, and some of the emails Clinton sent from her server have since been marked classified.

But none so far have been found to be marked classified at the time they were sent, which Clinton has repeatedly noted. Yet questions remain about the content of emails she deleted from the server before handing it over to the State Department. Clinton has apologized for using a private email address as Secretary of State, and her campaign has sought to shift its tone and carefully explain the details of a complicated issue to the public.

The poll was conducted among a national sample of 1,003 adults using both landline and cellphones, and has an overall margin of error of +/-3.5 percentage points.

[Washington Post/ABC]

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.