Syrian President Bashar Assad's informal invitation to US President Barack Obama earlier this month to visit his country has helped raise cautious optimism in some quarters that Syria could be ready to turn a new leaf. One US official has said that the Syrians have expressed "a genuine desire" to have a productive dialogue, raising the possibility that "they may be open to fundamentally changing their relationship with the United States and reentering the Arab fold." And on Saturday, special US envoy to the Middle East George Mitchell was in Damascus to discuss bilateral relations and reviving peace negotiations with Israel. After years of economic sanctions and isolation, Assad's regime appears eager to engage the United States and some experts even note a certain "moderation" in some of its recent behavior, particularly concerning Lebanon. But it has yet to show signs of a real policy shift vis a vis its ally Iran or its leading proxies. And just how far Syria, which wants to be acknowledged as a key player in the region, is willing to go to appease the United States has yet to be seen. In fact, the anti-US Shi'ite cleric Moqtada al-Sadr, who is very close to Iran, visited Damascus last week reportedly to strengthen relations with Iraqi resistance groups. "I don't see any major changes on Bashar's part," Andrew Tabler, an expert on Syria at the Washington Institute for Near East Policy, told The Jerusalem Post last week. "And whatever changes there are, [they] are very incremental and very hard for the US to pick up." Others, however, argue that Syria's recent behavior can be considered an attempt to keep some distance from the Islamic Republic of Iran. The Syrian regime, for example, did not interfere in Lebanon's hotly contested June 7 elections, which resulted in a victory for the Western-backed March 14 coalition over the Hizbullah-led opposition, says Abdel Monem Said Aly, director of the Cairo-based Al-Ahram Center for Political and Strategic Studies. In addition, both Hizbullah and Hamas, which are backed by Syria and Iran, have kept a relatively low profile in recent months and have refrained from launching rockets into Israel or creating other obvious mischief. "Certainly, some of it can be seen as a distance from Teheran, not a big distance, but a distance [nonetheless] can be noticed," Said Aly said. As part of its approach to cautious, critical engagement with Syria, Obama's administration announced in June that it will restore an ambassador to Damascus after a four year hiatus following the assassination of former Lebanese Prime Minister Rafiq al-Hariri. Damascus, which has denied any involvement, was widely believed to be behind the attack. But despite last month's announcement, the US has yet to name an ambassador. Security arrangements involving foreign fighters in Iraq have yet to be adhered to. And in neighboring Lebanon, where Syria still wields influence, the March 14 coalition and the Hizbullah-led opposition have yet to form a government more than six weeks after the country's general elections. "This all indicates to me that there are still a lot of bones of contention between Syria and the US," and even within the US administration on how to best deal with Syria, said Prof. Joshua Landis, co-director of the Center for Middle Eastern Studies at the University of Oklahoma. To improve relations with the US, Syria will have to make difficult choices concerning its support for foreign fighters in Iraq and radical groups like Hizbullah and Hamas. In addition to making progress on the Israeli-Syrian track, the Obama administration wants Syria to push Hamas to make up with Fatah to advance Palestinian reconciliation. Syria knows, too, that cracking down on al-Qaida and other jihadists inside its borders could result in retaliatory attacks against its minority-led regime or its facilities, Tabler said. "It's very hard to move forward on a peace process when there are American soldiers being killed in Iraq as a result of attacks by foreign fighters that are coming across from Syria," Tabler said, noting that about 90 percent of these fighters enter Iraq through Syria. The recent discovery of undeclared uranium at a second site in Syria by the International Atomic Energy Agency, which indicates some sort of nuclear program, also creates additional obstacles to engagement, he said. Furthermore, Syria's intentions regarding Iran, and its proxies Hizbullah and Hamas, are not very clear. "What I think is they want to be able to get the Golan [Heights] back in exchange for some sort of change in their relationship with Iran, which is not described, and where they can politically support Hizbullah and Hamas but perhaps without supplying them" militarily, Tabler said. This strategy, however, is complicated by parliamentary moves in Israel that would require a referendum to withdraw from the Golan Heights, which Israel captured in the Six Day War. "The question is: Are Israelis the kind of people that will give back the Golan [in a peace agreement] for a maybe?" Tabler said. "Probably not. I can't see it." Others note that the current right-wing Israeli government would be reluctant, in any event, to give up control of the strategic Golan Heights, which is a primary goal for Syria. America, too, which may be still formulating its own policy, will have to decide how clear of an answer it will be satisfied with from Syria regarding all of its files. While the Assad regime has an interest in decisions that are ultimately "shades of gray," the US wants to make things more or less clear cut, Tabler said. Landis believes that Syria is willing to take steps in both Iraq and Lebanon if America were to relieve economic sanctions in the country. But he also says that Syria is unlikely to significantly shift its policy unless it regains control of Golan Heights. The reason, he said, is that without the Golan, Syria's only leverage is its relationship with Iran and with its proxies, Hizbullah and Hamas - the three entities that are putting pressure on Israel. "If you give Syria the Golan and Israel were to get peace with Syria, then Syria is free in a sense to carry out this 180 [degree turnabout]," Landis said. "It can dump Iran and do some damage to its allies because it's getting something from America and Israel. But without that, why would Syria do a 180? What would it get from America?" Hilary Leila Krieger contributed to this report.