As of mid-July, it appears the American public still opposes ObamaCare, with the opposition strongest among those most likely to vote.
Judging by the latest data at the poll-aggregating site Pollster.com, a solid plurality of adults continues to oppose ObamaCare (46.8 vs. 40.1 percent):
The trendlines don't look so good for supporters of the law. (The public isn't so hot about President Obama's handling of health care, either.) Yet the above graph includes (polls that include) adults who are neither registered nor likely to vote.
If you want to know how public opinion about ObamaCare will influence the November elections, you'll want to look at polls of likely voters. Those suggest a majority opposes the law (51.3 vs 42.9 percent):
It's hard to know what to make of the trendlines, since the last poll of likely voters was in April and Pollster.com's trend estimates can be skewed if the most recent poll is aberrant.
Polls of registered voters (which include both likely and unlikely registered voters) again show that a majority opposes ObamaCare (50.7 vs. 42.7 percent). Compared to the graph of likely-voter-only polls, the "oppose" trendline appears flatter, while the "support" line appears to have the same slope:
Yet the "support" trend-estimate among registered voters started from a lower base, so that the July point estimate (42.7 percent) is roughly the same as that for likely voters in April (42.9 percent). And the most recent spread between opponents and supporters is roughly the same in the two graphs (8.4 vs. 8.0 percentage points).
Combining polls of likely voters and registered voters produces a higher ratio of likely-to-unlikely voters than looking at just registered voters. It also shows that a majority oppose ObamaCare (50.7 vs. 41.2 percent), with a persistent gap of about 9 percentage points:
(NB: The figures I cite in this post are the figures that appeared on these graphs on July 17. Since these graphs are embedded from Pollster.com, the figures in the graphs will change as as Pollster.com adds new polling data to their graphs.)