From the conclusion:
"US decision on a new strategy toward Iran will not wait. That is President-elect Obama's inheritance. Talking to Iran will be difficult. In the US, some political leaders and interest groups oppose better relations, though public opinion surveys suggest that a solid majority of Americans favor a diplomatic solution to US–Iranian differences over nuclear enrichment and other issues. Similarly, in Iran, an attempt to engage or compromise with the US will be attacked by factions seeking a political advantage, despite the hopes of millions of Iranians that the US and Iran find a way to improve relations. Suspicion dominates a relationship with a long history of grievances on both sides. Washington doubts the innocence of Iran's nuclear intentions, and Tehran suspects that America's real intent is regime change."
"Moreover, some analysts, including many Israelis, view Iran as an "existential threat" to Israel, object to Iran's backing of Hezbollah, and believe that Iran's support for Hamas undermines a two-state solution between Israel and Palestine. In addition, Iran's human rights record provokes understandable opposition internationally. These concerns are extremely urgent, but deteriorating relations between Washington and Tehran will only strengthen Iranian hard-liners and therefore exacerbate the human rights situation. US–Iranian hostility may also give Iran a greater incentive to exercise its leverage with Hamas and Hezbollah in ways that undermine a resolution to the Israel–Palestinian dispute. We believe that successful engagement with Iran on Iraq, Afghanistan, and the nuclear issue could translate into progress on other issues. Indeed, Iran's secret 2003 proposal for US talks included on its agenda Hamas, Hezbollah, and a two-state solution."
"The US can impose costs on Iran, but it cannot impose its will. The same is true for Iran. Progress requires on both sides a greater focus on strategy rather than tactics. Adopting a new, integrated approach will require political leadership that is disciplined and willing to take risks. There could be frustrations, setbacks and dangers, but the US and Iran can avoid a downward spiral that risks military conflict. They can also create an opportunity for progress on some of the most difficult and complicated challenges the US will have to confront in the coming years."