Apart from its many other faults and its overall one-sidedness, and despite its authors' claims to the contrary, the US plan for Israel-Palestine, unveiled at the end of January, proposes perilous changes to the historical status quo at Jerusalem's Holy Esplanade.

The 14-hectare (35-acre) compound, known to Jews as Temple Mount and to Muslims as al-Haram al-Sharif, is Judaism's holiest site and Islam's third-most sacred after Mecca and Medina. The contested site, which is home to both the Dome of the Rock and Al-Aqsa Mosque, is currently supervised by Jordan's Islamic Waqf according to an unwritten Ottoman-era arrangement. Per the arrangement, Muslims are allowed to pray at the site, while non-Muslims are only allowed entry as tourists.

In its plan, titled Peace to Prosperity, the Trump administration pays lip service to this arrangement, saying "the status quo at the Temple Mount/Haram al-Sharif should continue uninterrupted". Despite this, however, it calls for three major changes that would, in practice, undo the centuries-old arrangement completely: transferring the site to Israeli sovereignty, rescinding Jordan's custodianship over it, and ending the ban on non-Muslim prayer.

The plan aims to end Muslim control over the site, merely promising to guarantee Muslim worshippers' free access to it. It also seemingly attempts to do away with Jordan's custodianship of the compound, making no mention of it, a move that flies in the face of Israel's commitment in the 1994 Israel-Jordan peace treaty to "give high priority to the Jordanian historic role in these shrines". The plan instead describes Israel as a custodian of Jerusalem's holy sites.

The plan calls for freedom of worship at the Holy Esplanade, saying: "[p]eople of every faith should be permitted to pray on the Temple Mount/Haram al-Sharif, in a manner that is fully respectful to their religion, taking into account the times of each religion's prayers and holidays, as well as other religious factors". This seemingly benign notion - that there ought to be freedom of worship at the site - masks an attempt to make a major alteration to the historical status quo.

Regardless of what the notion means in practice - separate Jewish and Muslim devotions or side-by-side prayer - the mere possibility of separate prayer times triggers visceral Palestinian fears that Al-Aqsa Mosque will one day undergo a forced partitioning akin to the one imposed on Hebron's Ibrahimi Mosque by Israeli authorities in 1994.

The Trump plan is unlikely to ever serve as the basis for negotiations between Israel and the Palestinians, let alone a comprehensive peace deal. The Palestine Liberation Organisation and Hamas refused to engage with it long before its announcement. Some Arab states made somewhat supportive statements about it right after its publication but these were soon overtaken by a chorus of disapproval from around the world. The Arab League and Organisation of Islamic Cooperation also rejected the plan in early February.

The plan, however, can still cause considerable damage. Israelis could invoke it as setting forth new default parameters for how the site will be governed in the absence of an Israeli-Palestinian deal.

Following the Muslim world's rejection of the plan's attempt to alter the status quo at the Holy Esplanade, US Ambassador to Israel David Friedman sought to clarify Washington's stance on the issue. "The status quo, in the manner that it is observed today, will continue absent an agreement to the contrary," he said at a media briefing. "So there's nothing in the […] plan that would impose any alteration of the status quo that's not subject to agreement of all the parties".

In theory, Friedman's remarks provide some clarification, suggesting Washington will insist that any change allowing for non-Muslim prayer should occur only as part of an Israeli-Palestinian peace agreement. In practice, however, his comments leave room for ambiguity as "the status quo, in the manner that it is observed today" - in both Jordanian and Palestinian eyes - is already an eroded version of the historical arrangement.

Over the years, Israel has increasingly allowed Jewish prayer and imposed greater limitations on the Waqf's independence. Growing numbers of religious Jews have visited the site, many of whom are part of Temple movements - activist groups seeking to promote Jewish worship at and Israeli control over the holy site with the ultimate aim of erecting a Third Temple.

They make up a small minority of Israeli Jews, but Israel's police has given them significant leeway, tolerating low-profile prayer as well as discreet study of religious texts and conduct of rites of passage, while blocking open and loud prayer.

With Waqf support, Palestinians have regained access over three sections of the compound turning them into prayer halls. This happened most recently at a building near Bab al-Rahma which was shut down by Israeli authorities in 2003.

In light of all this, it is clear that there are major differences between committing to the ever-changing status quo today and the historical arrangement.

Tellingly, Public Security Minister Gilad Erdan, who is responsible for the police policies at the holy site, seems to publicly encourage ongoing Jewish prayer at the site, in contravention of the prayer ban.

Moreover, Temple activists have already been invoking the plan's language to argue for doing away with the non-Muslim prayer ban. The Students for the Temple Mount, for example, launched a media campaign within two days of the plan's release, titled "The Time Has Come: Sovereignty and Freedom of Worship at the Temple Mount for Jews Now!", quoting the Trump plan's statement in support of Jewish prayer.

There are many reasons to reject the plan, including its departure from international norms, its blatant bias, and its treatment of Palestinians in Israel as second-class citizens. But the positions it espouses on Jerusalem's Holy Esplanade present a particular danger.

By calling into question the status quo and legitimising exclusivist Israeli positions, it risks making any future resolution ever more elusive. It empowers forces working to shatter the ban on non-Muslim worship on the site and increases the possibility of another episode of religiously motivated violence in Jerusalem.

The US is assertively seeking backing for its plan, including from Arab states. Should President Trump be re-elected in November, his administration may well embark on a more sustained effort to do so. Those hoping for a peaceful and sustainable resolution to the Israeli-Palestinian conflict should not just withhold their support for it serving as the basis for negotiations, but actively oppose it.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial stance.