(CNN) Anyone interested in a just and durable resolution to the Palestine-Israel conflict should be disturbed watching the Donald Trump transition unfold.

As Israel's military occupation over Palestinian land is set to mark 50 years in 2017, the President-elect has nominated David Friedman, a right-wing sponsor of Israel's illegal settlement enterprise, to serve as US ambassador to Israel. And in a move that defies decades of tradition, it's been reported he is also taking an active role in shaping diplomatic efforts; there are reports that Israel asked Trump for help in getting the US to veto a Security Council resolution demanding an end to Israeli settlements — proposed and then delayed by Egypt, and subsequently passed on Friday. Ultimately the United States abstained.

Friedman, a bankruptcy lawyer with no relevant experience, is president of the US fundraising arm for Bet El, a settlement built on occupied Palestinian land in the West Bank. His extremist record includes calling President Obama an anti-Semite and labeling American Jews who criticize Israel's military occupation "kapos," a term used for Nazi collaborators. At a time when bold US leadership is required to stop the Israelis from flying off a cliff, destroying any chance of peace, Friedman is the exact opposite of who we need in a diplomatic position.

Both Trump and Friedman have promised to move the US embassy to Jerusalem, thereby recognizing Israeli sovereignty over the city. At best, in one fell swoop Friedman would serve to normalize the acquisition of territory by force. At worst, such reckless disregard for international law and the highly sensitive issues involved could egg on a diplomatic Armageddon.

Friedman is simply the latest in a string of indicators underlining the President-elect's intention to dismantle US policy going back to the Carter administration acknowledging that Israeli settlement construction in the occupied Palestinian territories violates the Fourth Geneva Convention, which states that an occupying power cannot transfer parts of its own civilian population into the territory it occupies.

Though Secretary of State John Kerry said recently at the Saban Forum that the failure of peace talks is largely attributable to Israel's continued settlement construction, Trump has said he thought more settlements — not less — should be built in the occupied West Bank, including East Jerusalem. That wasn't just campaign bluster. Trump reportedly donated $10,000 to Friedman's settlement fund well before his run for the presidency.

The settlement in question, Bet El, is located deep in the West Bank, on Ramallah's doorstep, and only meters away from Palestinian Authority President Mahmoud Abbas' home. Trump's son-in-law and adviser, Jared Kushner, whom the President-elect implausibly suggested could assist with brokering an Israel-Palestine peace agreement, is reported to have contributed through his family foundation to the same.

The settlement in question, Bet El, is located deep in the West Bank, on Ramallah's doorstep, and only meters away from Palestinian Authority President Mahmoud Abbas' home. Trump's son-in-law and adviser, Jared Kushner, whom the President-elect implausibly suggested could assist with brokering an Israel-Palestine peace agreement, is reported to have contributed through his family foundation to the same.

This potential future of America's Israel policy, shaped by Friedman, is indeed grim, prompting the international community to speculate about what Obama could do before leaving office to preserve the two-state solution. Some believe he won't do anything significant, despite the fact that according to a poll released by the Brookings Institution, 70% of Democrats and a plurality (46%) of all Americans favor some sort of US action at the United Nations.

Instead of abstaining from Friday's vote, the United States could finally have taken a meaningful stand against illegal settlements by supporting the resolution. This would have been in line with longstanding US policy opposing Israeli settlements —policy the United States has tragically not enforced — as well as with US public opinion.

In spite of the abstention, another option left to Obama is to recognize the state of Palestine on the 1967 borders, as former President Jimmy Carter has recommended. This would also send a clear message about the illegitimacy of Israeli settlements and the right of Palestinians to live free from military occupation and foreign domination.

Let's be clear: If Obama chooses not to act, he will hold the distinction of being the US president responsible for cementing Israel's occupation over Palestinian land indefinitely, which many observers, including no fewer than four former Israeli prime ministers, have compared to apartheid. In April 2014, Kerry warned Israel was in danger of becoming an apartheid state if a two-state deal was not reached soon. While it's true President-elect Trump may radically alter US policy, Obama still has a chance to salvage his own legacy in Palestine and Israel after spending the last eight years warning of the dangers of Israeli rejectionism and settlement growth while failing to take any concrete action to stop them.

The United States can and must demonstrate principled leadership. If Obama is truly concerned with the fate of Israelis and Palestinians, with US foreign policy objectives in the Middle East, or with US national security, one thing he can't afford to do is nothing. A bold move by Obama can help advance the cause of Palestinian freedom in the international arena, and move US discourse on Palestine and Israel forward before Trump and Friedman come to power. The policies of the incoming Trump administration may still cause havoc, leading to accelerated settlement growth and the death of the long-endangered two-state solution. But at least there will be a precedent for future American leaders to take stronger action to help bring peace to the region.