The new Palestinian unity government of Fatah and Hamas puts the lie to fundamental assumptions on which the U.S. approach to Israeli-Palestinian peace have long rested, most prominently within the Obama administration.

Washington has long assumed that a two-state solution is attainable, that “land for peace” is the formula for success, that the key remaining issue is final borders for a new “Palestine,” that the main obstacle is Israeli settlements in the West Bank and East Jerusalem, and that Palestinian Authority President Mahmoud Abbas is the rare Palestinian leader who will make peace and deserves Israel’s support. With the terrorist group Hamas (which runs Gaza) now sharing power with Fatah, the ruling party of the Palestinian Authority (which runs the West Bank), the new Palestinian government undercuts all of these central assumptions.

Indeed, as this newly unified Palestinian leadership makes abundantly clear, the far more fundamental problem is broad Palestinian rejection of Israel to begin with and, with that, continuing Palestinian hopes of a new Palestine “from the [Jordan] River to the [Mediterranean] Sea.”

Almost certainly, apologists for the U.S. approach to Israeli-Palestinian peace-making, whether in the administration or outside it, will explain that the Fatah-Hamas agreement is something that it isn’t. They’ll tout the new government as a sign of Hamas’ moderation, or they’ll predict that a governing role will force Hamas to moderate its approach to Israel, or they’ll explain that Abbas’ willingness to team with Hamas proves his desire for a peace that includes both the West Bank and Gaza.

Don’t believe any of it.

Abbas, the former top aide to Palestinian terror mastermind Yasser Arafat, is now partnering with a terrorist group that remains dedicated to Israel’s destruction. That may surprise some U.S. officials, but it won’t surprise those who watch Abbas closely and track his activities in the West Bank. During his supposedly “moderate” presidency, Abbas has honored Israeli-killing Palestinian “martyrs” and “pioneers” – the latter of whom include Grand Mufti of Jerusalem Hajj Muhammad Amin Al-Husseini, who worked with Hitler during World War II and planned to adopt his “final solution” for the Middle East.

In addition, Abbas refuses to recognize Israel as a Jewish state and promotes the “right of return” of all Palestinian refugees, which would end the majority-Jewish status of Israel. And for all his supposed eagerness to make peace, he consistently imposes preconditions on Israeli-Palestinian peace talks, whether a freeze on settlements or the release of more Palestinian murderers from Israeli prisons.

Nor, despite the theory of optimists, has the responsibility to govern moderated either the Palestinian Authority or Hamas. In the West Bank, according to the State Department’s latest annual human rights reports, the authority restricts the freedoms of speech, press and assembly, and it allows for abuses of women, children and people with disabilities. Meanwhile, Abbas, who was elected president in 2005, has subverted the democratic process as he continues to serve even though he was supposed to step down in 2009.

Nevertheless, the West Bank is a democratic paradise compared to Gaza under Hamas.

Founded in 1987 as an offshoot of the Muslim Brotherhood, Hamas won Palestinian parliamentary elections of 2006. Rather than operate within the system, however, it ousted the Palestinian Authority from Gaza in a violent coup a year later.

The Fatah-Hamas civil war not only left the Palestinian territories divided. It left Hamas free to pursue a strict Islamist state on its narrow strip of land on the Mediterranean, while harassing, jailing, torturing and killing its opponents.

Over the last seven years, Hamas has launched, or permitted other terrorist groups to launch, thousands of rockets into southern Israel, terrorizing the Israeli men, women and children of Sderot and elsewhere. In fact, the rockets continued to fly in recent days as Fatah and Hamas came together.

Now, Hamas plans to retain the Izz al-Din al-Qassam Brigades, its Gaza-based militia, leaving the terrorist group positioned to strike Israel. With Hamas sharing power and retaining its military, the Palestinian territories could come to resemble Lebanon, where Hezbollah shares power and operates militarily.

Soviet dissident Andrei Sakharov famously cautioned, “A country that does not respect the rights of its own people will not respect the rights of its neighbors.” What was true of the former Soviet empire applies in spades to the new Palestinian unity government. It will not make peace with Israel, and neither borders nor settlements will change that reality.