Abbas has come under increasing pressure over his failure to deliver so far, six weeks on from the launch of the "roadmap" for peace at a summit in Jordan also attended by Israeli premier Ariel Sharon (news - web sites) and US President George W. Bush (news - web sites).
Israel has refused to sanction the release of the vast majority of the estimated 6,000 Palestinians in its prisons, Jewish settlement outposts have reemerged after a handful were dismantled in an initial blaze of publicity, and Palestinian leader Yasser Arafat (news - web sites) remains confined to his offices in Ramallah.
According to Diana Buttu, a legal adviser to the Palestine Liberation Organisation (PLO), anger is growing on the streets against Abbas and Washington must make Israel "hear the word stop" to prevent him from becoming a footnote in history.
"Israel has taken all the commitments and achievements of the Palestinians, put them in its pocket and given nothing back," she told AFP.
Buttu said that Washington was in a position to apply huge pressure on Israel as the country's main benefactor, in particular over settlement activity and the release of Palestinian prisoners.
"If Israel does not release the prisoners, people are going to look at the Palestinian Authority (news - web sites) and say 'you have become the security sub-contractor' of Israel" and turn their backs for good on the moderate approach of Abbas.
The radical Palestinian groups Hamas and Islamic Jihad have already said that Abbas' trip to the United States is a mistake, and that any pledges of funds that are made while he is in Washington are unacceptable "bribes".
Both organisations announced a three-month halt to anti-Israeli attacks late last month, but their patience has been sorely tested by Israel's refusal to so far release of any of its members from prison.
Israeli Prime Minister Ariel Sharon, who will also be in Washington later this month, will meet Abbas early next week when he is expected to make a confidence-building gesture on the prisoners issue.
The announcement of Abbas' visit, which was made late Wednesday, took many by surprise as it was thought he was unlikely to travel to Washington while Arafat was effectively confined to Ramallah by the Israelis.
Senior Arafat adviser Ahmed Abdulrahman said that the veteran leader had approved the visit, but regarded it as a "decisive" test to see whether the US was really prepared to exert influence on its chief regional ally.
"American efforts are very important and we hope from this visit to see serious American pressure on the Israeli government to completely implement the roadmap with withdrawals from Palestinian areas," he told AFP.
Otherwise "the roadmap will be like Tenet and Mitchell", two previous US blueprints to end Israeli-Palestinian violence which have bitten the dust.
Abbas will be accompanied on his July 25 trip by foreign minister Nabil Shaath, finance minister Salam Fayad and his security chief Mohammad Dahlan.
Dahlan's spokesman, Elias Zananiri, said that the delegation would impress on the Bush administration that "the Palestinians are not happy with the pace with which the Israelis" are implementing the roadmap.
"Without having real change on the ground, it's very difficult for Abu Mazen and his government to function," he told AFP, using Abbas' nom-de-guerre.
"We are trying to persuade the Palestinian people that there's light at the end of the tunnel." The United States could use its influence to "switch it on", he added.
An editorial in Thursday's leading Israeli daily Haaretz said that Abbas' position and the truce were being jeopardised.
"The PA and its prime minister ... cannot point to a single tangible achievement since the Aqaba summit" in Jordan on June 4, it said.
"Israel has an enormous interest in strengthening the ceasefire and especially Abbas' ability to rule. Foot-dragging on the prisoner releases, the suspension of the removal of outposts and a miserly approach to allowing freedom of movement are a guarantee of achieving the opposite result," the editorial warned.
