(CBS News) A new survey suggests that the Supreme Court's decision last week to uphold the Affordable Care Act, President Obama's landmark health care law, has negatively influenced many Republicans' opinion of the nation's highest court. It has also, the survey found, improved Democrats' perceptions of the court.
The Supreme Court on Thursday announced its decision to uphold the law nearly in its entirety, with five justices voting in its favor and four against. Chief Justice John Roberts, who has largely voted with conservatives in the past, surprised many by casting the decisive fifth vote siding with the more liberal justices. He also wrote the decision for the majority.
The CNN poll, conducted June 28-July 1, suggests the health care decision - and Roberts' breaking with party lines - made a deep impression on Republicans and Democrats alike. Among Democrats, the court's approval rating jumped by 23 percent, from 50 to 73 percent, after the decision. Among Republicans it fell by almost as much - 21 percent - to just 31 percent overall. Approval among independents ticked up by 5 percent following the decision.
Public opinion of Roberts has taken a similar turn. Forty-one percent of respondents in the poll said they had a favorable view of the chief justice, 24 percent had an unfavorable view, 21 percent said they had never heard of him, and 14 percent had no opinion. Most Democrats - 51 percent - were in the camp supporting Roberts, while only 30 percent of Republicans felt the same way.
When it comes to the law itself, 50 percent say they agree with the court's ruling, while 49 percent disagree. Those percentages also largely follow party lines, with most Democrats supporting the decision and most Republicans disagreeing with it.
"As recently as April, Republicans and Democrats had virtually identical positive opinions on the Supreme Court. But not any more," CNN Polling Director Keating Holland said of the poll. "That's the biggest change that the court decision has created."
In recent years, Americans have increasingly seen the Supreme as politically polarized. Republican-appointed judges have largely voted in line with the views of Republican politicians, while Democrat-appointed judges tend to vote in line with Democrats. After the health care decision was unveiled last week, Democrats welcomed Roberts' vote as a sign that the court might be less politically-driven than many had come to assume.
On Sunday, CBS News' Jan CrawfordRoberts had initially planned to vote against the law, but later changed his position and formed an alliance with liberal justices to uphold the law.
Crawford writes that Roberts may have been swayed by reports warning that the court - and Roberts' reputation along with it - would be damaged if the health care law, or major parts of it, was overturned.
"It is not known why Roberts changed his view on the mandate and decided to uphold the law. At least one conservative justice tried to get him to explain it, but was unsatisfied with the response, according to a source with knowledge of the conversation," Crawford wrote.