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Support for the war in Afghanistan has dropped to a new low in ABC News/Washington Post polls, surpassing even the war in Iraq at its most unpopular. Six in 10 Americans believe most Afghans themselves oppose the U.S. mission. And after a shooting rampage allegedly by a U.S. soldier, eight in 10 say the military should improve mental-health monitoring and limit combat duty alike.

Two-thirds of Americans now say the war in Afghanistan has not been worth fighting, a new high that matches peak opposition to the Iraq war almost exactly five years ago. Support for the Afghanistan war, at just 30 percent, is 3 points lower than the lowest on record for Iraq.

Views on the war were virtually as negative last spring, then improved after the killing of Osama bin Laden. The subsequent erosion follows the U.S. military's inadvertent burning of the Koran and other Muslim holy texts at Bagram Air Base in February, violent protests that followed and, separately, the massacre of 17 Afghan civilians in Kandahar in March, allegedly by a U.S. service member.

In an ABC/Post poll last month, after the Koran burning and related protests, opposition to the war increased from 54 percent to 60 percent, with just three in 10 believing Afghans themselves supported U.S. efforts in their country. Now, after the civilian massacre, opposition to the war has risen by another 6 points, to 66 percent, and the belief that Afghans support the war has dropped by 8 points, to 22 percent.

The drop in views that Afghans themselves support U.S. efforts makes a difference. This poll, produced for ABC by Langer Research Associates, finds that among those who think most Afghans back the war, a majority - 53 percent - think it's been worth fighting. Among those who think Afghans are opposed to what the U.S. is trying to accomplish, however, just 22 percent think the nation's longest war has been worth it.

KANDAHAR SHOOTING - While there's been speculation about the possible role of post-traumatic stress disorder or battlefield fatigue in the attack on Afghan civilians, the public divides, 44-43 percent, on whether this was an isolated incident or indicative of broader problems with the way the U.S. military monitors the mental health of service members.

Still, apart from the specific incident, there is a broad sense that the military should be doing more to track mental health - 79 percent say so - and to limit the amount of time active duty service members are deployed to combat areas, favored by an almost identical 80 percent. Just 14 and 15 percent, respectively, think the military already is doing enough mental health monitoring and that time limits on deployments are not needed.

Views of the civilian massacre are intertwined with broader views about military mental health screening. Among those who see the attack on civilians as indicative of broader problems, a near unanimous 93 percent think the military should be doing more to track the mental health of its members. Among those who view the attack as an isolated incident, the belief that the military should be doing more is 25 points lower, but a still broad 68 percent.

PARTISANSHIP and GROUPS - Support for the war in Afghanistan, views of the attack on civilians and support for greater mental health screening divide along partisan lines. A quarter of Democrats, three in 10 independents and 44 percent of Republicans think the war has been worth fighting. While still the most supportive of the war, Republican backing is at an all-time low. But independents and Democrats just are 2 and 6 points from their lows, respectively.

Republicans also are more apt to think Afghans themselves support U.S. efforts in their country - but still just 31 percent think so, compared to 21 percent of Democrats and independents.

Democrats are most likely to think the civilian massacre is indicative of a wider problem (51 percent), and to think the military should be making greater efforts in monitoring mental health (90 percent). Republicans are the least likely to share these views (33 and 70 percent, respectively), and as is customary, independents fall in between the two.

The pattern is similar among ideological groups, with liberals more likely than conservatives to view the shooting incident as indicative of a broader problem and to back more stringent mental health screening, while moderates fall in between.

Among other groups, women are 15 points more likely than men to see the shooting incident as part of a broader problem in the military, 51 to 36 percent. They're also 16 points more likely to think the military should be doing more to monitor mental health (87 vs. 71 percent) and 13 points more apt to want limits on the amount of time service members can spend in combat zones (86 to 73 percent).

OBAMA - Although the war in Afghanistan now rivals the Iraq war in unpopularity, President Obama, so far, has escaped much damage. While support for the war has dropped by 13 points since July, approval of his handling of it is down a scant 5 points to 48 percent. His overall approval, moreover, has risen from a low of 42 in October to 50 percent now.

Yet political risks remain, especially in an election year. Broad discontent with the war in Iraq had severe consequences for George W. Bush's presidency, helping to push his overall approval rating below 25 percent. The question for Obama is the extent to which his withdrawal strategy can continue to hold greater criticism at bay.

METHODOLOGY - This ABC News/Washington Post poll was conducted by telephone April 5-8, 2012, among a random national sample of 1,003 adults, including landline and cell-phone-only respondents. Results have a margin of sampling error of 4 points for the full sample. The survey was produced for ABC News by Langer Research Associates of New York, N.Y., with sampling, data collection and tabulation by Abt-SRBI of New York, N.Y.