WASHINGTON (AP) — Public approval of the Supreme Court has fallen following the leak of a draft opinion that would overturn the Roe v. Wade decision guaranteeing abortion rights nationwide, according to a poll.

Disapproval of the nation's highest court was especially pronounced among the roughly two-thirds of U.S. adults who oppose overturning Roe, while support for the court was high among those in favor, according to the Marquette Law School Poll, which also found increased partisan polarization in approval.

The draft opinion obtained by Politico would overrule Roe and Planned Parenthood v. Casey, the 1992 decision that reaffirmed the right to end a pregnancy. Chief Justice John Roberts confirmed the draft was authentic and ordered an investigation, led by Supreme Court Marshal Gail Curley, to try to find the source of the leak.

The official opinion is expected to be released sometime in the next month. The case involves a Mississippi law that would prohibit abortion after 15 weeks, but if the justices go further and eliminate the abortion right first announced in Roe, roughly half the states are expected to ban or severely restrict abortion.

In the Marquette poll, 55% disapprove of the court, up from 45% in March. Approval was down a corresponding 10 percentage points, from 54% to 44%.

Among people who oppose overturning Roe, 74% disapproved of the court in the new poll, compared with 54% in March. Eighty-four percent of those who favor jettisoning the court's main abortion precedents voiced approval of the institution, up from 65% two months ago.

Approval was fairly steady among Republicans from March to May, but fell sharply among Democrats and slightly among independents.

The survey, conducted starting about a week after the leaked document, shows further erosion in public support for the court; confidence in the court had started to decline in polling last year.

In September, the Marquette Law School Poll, among other surveys, found a drop in approval of the court following its vote to allow a restrictive Texas abortion law to take effect.

Views on abortion in the new poll were consistent with earlier surveys, with about two-thirds of U.S. adults saying they oppose overturning Roe.

Other polls, including those conducted by The Associated Press-NORC Center for Public Affairs Research, also have consistently shown only about 1 in 10 Americans want abortion to be illegal in all cases. A majority are in favor of abortion being legal in all or most circumstances, but polls indicate many also support restrictions especially later in pregnancy.

The new Marquette poll showed Americans were evenly divided over the Mississippi law outlawing most abortions after 15 weeks of pregnancy, similar to views earlier in the year.

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The poll of 1,004 adults was conducted May 9-19 using a sample drawn from the probability-based SSRS Opinion Panel, which is designed to be representative of the U.S. population. The margin of sampling error for all respondents is plus or minus 3.9 percentage points.