There is a commonly held view that taking military action against terrorists has the counterproductive effect of strengthening their popular support. Recent polling data suggest that Israel's recent action in Gaza had precisely the opposite effect. It turns out that military defeat (Israeli forces killed hundreds of Hamas fighters and damaged its infrastructure, while taking few losses of their own) actually lowered Hamas' support among Palestinians. A new poll by the Palestinian Center for Public Opinion found that 51% of Palestinians and 56% of those living in the Gaza Strip now believe that Hamas is leading Gaza in the "wrong" direction. Only 28% of Gaza Palestinians say they support Hamas, down from 52% in a survey conducted in November, before the recent conflict.
These survey results may well actually overstate the degree of popular support enjoyed by Hamas in Gaza. We know from previous experience that polls conducted in repressive societies are often unreliable because respondents are afraid to express views critical of the government, for fear of arrest or other punishment. Hamas, of course, has often killed or imprisoned supporters of the rival Fatah faction (see, e.g., here), and is currently engaged in a new roundup of their political opponents occurring around the same time as the PCPO was conducting its poll. As one Gaza Palestinian recently told a reporter when asked whether he thought that the war had weakened Hamas' support, "If I talk about this, I'm afraid that Hamas will come and kill me." I'm sure that the PCPO researchers make every effort to ensure the confidentiality of respondents. But some Gaza Palestinians may be unwilling to bet their lives on it.
To say that the Israeli success reduced support for Hamas is not the same thing as saying that it caused Palestinians to take a more favorable view of Israel. The same poll shows that 54% blame Israel for the recent hostilities, with only 15% blaming Hamas (though these results too may be affected by lying due to fear of retaliation). But the Israelis don't need Palestinians to like them. Their more immediate need is to persuade Palestinians to stop supporting terrorism.
It is not surprising that military setbacks have reduced Hamas' popular support. We can see similar patterns throughout history. German support for Nazism collapsed because of Hitler's massive military defeat. In the Arab world, previously strong support for Egyptian dictator Gamal Abdel Nasser's ideology of pan-Arabism plummeted after his defeat in the Six Day War. Here in the United States, support for neoconservative hawkishness declined greatly as a result of setbacks in the occupation of Iraq. Most people are highly biased in their evaluation of political information, and tend to reject anything that cuts against their preexisting beliefs. But clear military defeat is such an obvious setback that all but the most committed ideologues find it difficult to ignore or explain away.
The fall in Hamas' popular support does not by itself justify Israel's recent policies. But it does provide an important data point in the longstanding debate over the impact of military action on public support for terrorists. It turns out that you can cause that support to drop - if you win.
NOTE: I know from previous experience that comments about issues related to the Israeli-Palestinian conflict produce a very high ratio of heat relative to light. As per my usual practice, I'm not going to aggressively police the comments. But I would suggest that we will have a better discussion if commenters focus on the specific issue raised in the post rather than on the broader rights and wrongs of the conflict. I highly doubt that we can say anything about the latter that hasn't already been repeatedly stated elsewhere.
UPDATE: It's worth noting the contrast between these poll results and data showing that the 2006 conflict between Israel and Hezbollah led to increased Lebanese popular support for the latter. I conjecture that the difference is due largely to the fact that Israel was perceived as the loser of that war, or at least as failing to win.