A few days ago, during a meeting at the White House with visiting Palestinian Authority President Mahmoud Abbas, US President Barack Obama made an important statement, calling for a new approach to allowing Gazans to trade freely with the world while protecting Israel’s legitimate security needs.

It sounded to many, including myself, like a serious and sensible shift in policy, and a long-needed one. Why, then, does it generate mainly yawns and disbelief?

Consider this for starters: A year ago, Obama forcefully declared in a speech in Cairo that the United States sought to forge strong, mutually respectful relations with the people of the Islamic world. Arab, Islamic and world perceptions of Obama soared, sparked by a new sense of hope that the American presidency and people were now motivated by reason and compassionate self-interest, rather than the nearly imbecilic militancy and pro-Israeli fanaticism of the George W. Bush years.

A year later, though, according to a new poll by the respected Gallup Survey, those gains in favourable views abroad that the United States achieved are dissipating.

Four out of six Arab League countries Gallup has surveyed each year since 2008 “are now less approving of US leadership than they were in fall 2009”. Egyptians' approval ratings dropped 18 percentage points, followed by Algerians at 13 points. These declines reverse the approval gains in Egypt (+19 points) and Algeria (+22 points) recorded after Obama's inauguration in 2009, and the further approval boosts registered after Obama's Cairo address (12 points in Egypt).

The simple conclusion is that Arabs and others around the world judge the US by what it does, not by what it says.

Obama is now a man with a track record, no longer mainly the refreshing breeze of sincerity and change he was 18 months ago. His words, henceforth, will no longer be judged mainly in contrast with the bombast and buffoonery of the Bush crowd who was so deeply buttressed by the pro-Israeli lobby zealots in Washington and the allied Christian fundamentalists who walked a fine line between divine inspiration and political lunacy.

So it is noteworthy when Obama articulates a change in policy, as he seemed to do this week, following the Israeli naval attack on humanitarian aid ships, when he said that Israel should sharply limit its blockade of Gaza, called the situation there “unsustainable” and said: "The key here is making sure that Israel's security needs are met but that the needs of people in Gaza are also met. So if we can get a new conceptual framework ... it seems to me that we should be able to take what has been a tragedy ?nd turn it into an opportunity to create a situation where lives in Gaza are actually, directly improved."

These are welcome words that reflect a sensible approach. But will they be translated into policy and actions on the ground?

Judging by the year following Obama’s Cairo speech, the answer must lean towards the sceptical, if not the explicitly negative.

A man who generated respect and hope 18 months ago, Obama today still generates respect, but appreciably less hope or expectation of changes in policies when the issues at hand are linked in any way to Israel and its interests.

The Gallup poll is also instructive because it provides useful insight into the issues that people in the Arab world care about. Any changes in US policies - such as the one Obama now dangles before us for Gaza - will enjoy legitimacy and efficacy if they respond to the legitimate grievances and rights of all concerned, in this case mainly the Israelis and Palestinians.

The large swings in Egyptians’ perceptions of Obama, the Gallup analysts said, “may reflect a perceived lack of progress on the issues many Egyptians said in May 2008 were most significant to improving their opinion of the United States: pulling out of Iraq, removing military bases from Saudi Arabia, supporting the rights of Muslims to elect their own governments, promoting greater economic development, closing Guantanamo Bay prison, and greater technology transfer and exchange of business expertise.”

A separate Egyptian survey after the Cairo address also found that Egyptians most likely identified the Palestinian-Israeli conflict as the most important issue in the president's speech. An American policy that simultaneously acknowledges the sovereign and human rights of the Palestinians as well as Israelis’ security and acceptance needs is likely to be widely acclaimed.

So the return this week of high-profile, high-intensity and high-stakes Obama talk on a critical issue such as relieving the Israeli siege of Gaza is a new opportunity to explore two important phenomena: what drives this impressive, earnest young American president to say such sensible things, and does he actually mean anything of what he says?