Washington (CNN)A majority of Americans want Congress to reject the recently-negotiated nuclear deal with Iran, even as President Barack Obama's approval rating continues to stand in net-positive territory for the second month in a row, according to a new CNN/ORC poll.

The new CNN/ORC poll finds 49% approve of the way Obama is handling his job, 47% disapprove, about the same as in a June survey, which found the President's approval rating at 50% for the first time since 2013. But on the President's biggest accomplishment since then -- the nuclear agreement reached between the U.S., its allies and Iran -- most say they would like to see Congress reject it. Overall, 52% say Congress should reject the deal, 44% say it should be approved.

Some opposition to the deal may be fueled by skepticism. A CNN/ORC poll in late June, conducted as the deal was being worked out, found that nearly two-thirds of adults thought it was unlikely the negotiations would result in an agreement that would prevent Iran from developing nuclear weapons.

The new poll finds a sharp partisan gap on whether Congress should approve the deal, with 66% of Republicans and 55% of independents saying Congress ought to reject it and 61% of Democrats saying it should be approved. Younger adults, who tend to lean more Democratic, are more apt to favor the deal: 53% of those age 18-34 say approve it, while 56% of those age 35 or older say reject it. There is also an education divide on the deal, with 53% of college graduates saying the deal should be approved, while just 37% of those with a high school degree or less formal education saying they think it should be approved.

On the economy, the optimism that emerged earlier this year has wilted in the summer heat. Just 41% of Americans say the economy is in good shape, with 59% describing it as poor. That's a sharp negative shift since April, when 52% said things were in good shape.

During that time, most U.S. economic indicators have remained positive, though the stock market has fallen recently amid international financial turmoil in Greece and China.

And in a bad sign for the President, much of that growing negativity about the economy comes from those in his own party, particularly younger Americans. Among Democrats, 58% call the economy "good," but that's down 18 points since April, when 76% said it was very or somewhat good. Declines over that time among independents (down 10 points to 37%) and Republicans (down a statistically insignificant 3 points to 28%) were much smaller. And among young people, who were a key component of Obama's electoral coalition in 2008 and 2012, the share of adults age 18 to 34 who think the economy is in good shape has fallen 17 points to 38%.

Still, on a personal level, Americans are beginning to feel better off. The poll finds people are more likely to say their personal situation has improved under Obama's second term than they were three years in to his first term. Overall, 49% say they're doing better now than they were three years ago, in the run up to Obama's re-election. Fewer, 38%, say their personal situation has not improved. Americans' assessment of their own personal finances under his first term were much less rosy. In September 2011, 58% said they were not any better off than three years earlier, while just 32% said they were better off. That shift is evenly spread across most partisan and demographic divides.

The CNN/ORC International Poll was conducted by telephone July 22-25 among a random national sample of 1,017 adults, including 898 registered voters. Results for all adults have a margin of sampling error of plus or minus 3 percentage points.

By CNN