Positive views of the Republican Party have fallen 18 points since January

The percentage of those with favorable views of the Republican Party has dropped across the board since early this year, including sharply among Republicans, a Pew Research Center poll says. 

Fewer than a third of Americans, 32 percent, have a favorable impression of the GOP, a 9-point drop in the poll since January. Pew's survey finds that 60 percent have an unfavorable view.

 Positive views of the Republican Party have fallen 18 points since January among those who identify as Republican, from 86 to 68 percent. 

It has also fallen 8 points among Independents since then, from 37 to 29 percent. 

Meanwhile, the Democratic Party's ratings are closer — 48 percent favorable to 47 percent unfavorable — and Democrats' views on their party have remained steady, 86 percent favorable, during the GOP's dip.

Pew's latest poll was conducted early last week amid a nascent 2016 presidential race that has been dominated in the media by businessman Donald Trump since he launched a White House bid in mid-June.

Trump, a Republican candidate, has enjoyed weeks of attention for his controversial comments on "rapists" and other criminals coming across the border from Mexico, fizzled business ties and intra-party jabbing. 

Despite the controversy, he sits atop a crowded GOP field in recent polling.

Pew's survey of 2,002 U.S. adults was conducted July 14-20 via landlines and cellphones with a margin of error of 2.5 points.

Why the drop among Republicans? - HuffPollster asked their followers on Twitter for their their best guesses and two theories emerged. First, a sense of disappointment that the Republican majorities have not made progress on their agenda, and perhaps have lost further ground to President Obama. Second, in one word, "Trump", or more broadly the "chaos" in the 2016 field. Some highlights:

-Richard Freedman (R): "GOP has not stopped ACA, moved to secure border, reduced spending in logical manner, etc. While generally not...possible, disappointing. Also primary looks like clown show from afar. [@richfreed here and here]

-Brian Stryker (D): "Perceived impotence? Obama/libs lots of recent wins, and GOP just hasn't had a lot of chances to block things up" [@BrianStryker]

-Conn Carroll (R): "what has the GOP Senate accomplished since January exactly?" [@conncarroll]

-Michelle Diggles (D): "Republicans expect their leaders to get their way. When they don't (e.g., ACA not repealed) feel lied to." [@MichelleDiggles]

-Matt Dabrowski (R): "Portions of the base continue to be strongly dissatisfied. At the risk of being reductive, this is the Ted Cruz story." [@MattDabrowski]

-Greg Dworkin (D): "Trump...with a dollup of losing important SCOTUS cases." [@DemFromCT here and here]

Drop since December as strong among conservative Republicans as among moderates - HuffPollster asked Pew Research to break out the trend among Republicans by self-reported ideology. While the drop since January is slightly steeper among conservatives than other Republicans, there is little difference since December. Given the relatively small samples sizes, especially for moderate-to-liberal Republicans (just 139 interviews on the most recent poll), the changes are essentially indistinguishable.