Dennis Ross, a counselor at the Washington Institute for Near East Policy, was a special assistant to President Obama on the Middle East and a senior director on the National Security Council staff from July 2009 to December 2011.

A new reality and an alternative reality are shaping up in Egypt. President Mohamed Morsi and the Muslim Brotherhood appear firmly in control . Morsi seized on the killing of 16 Egyptian soldiers in the Sinai early this month — an embarrassment for the military and particularly the Supreme Council of the Armed Forces ( SCAF ) — to remove the most senior military leaders from office. He also unilaterally amended the March 2011 constitution declaration and gave his office executive and legislative powers. In short, with no hint of resistance from the military, Morsi has imposed civilian leadership on Egypt.

Many see Morsi’s move to control the SCAF — he sacked Field Marshal Mohammed Hussein Tantawi; military chief of staff Sami Anan; and the heads of Egypt’s army, navy and air force — as finally giving Egypt’s revolution the chance to remove key remnants of the Mubarak regime and fulfill its promise. Others, particularly non-Islamists, are more prone to see recent actions as the Muslim Brotherhood removing any checks on its power.

Given some of the other moves that Morsi and those around him have made, there is reason to be concerned. Morsi has appointed a new minister of information, Salah Abdul Maqsud; he, too, comes from the Muslim Brotherhood and actively supports the move to replace 50 leading editors and journalists. Charges have been filed against the editor of the independent opposition newspaperal-Dustour for insulting the president. It is probably no accident that the state media’s tone has changed markedly in the past week — and is far more favorable toward Morsi.

None of this means that Egypt’s path of change is foreordained. It does mean that the president, who has largely surrounded himself with members of the Muslim Brotherhood or sympathizers, dominates all of Egypt’s institutions of power. He and the Brotherhood will find it hard to escape responsibility for whatever happens in Egypt. The country faces daunting economic challenges; it will need significant outside assistance and private investment. Morsi and the Brotherhood are seeking outside support for their “renaissance plan” to revitalize the economy; after they resisted the conditions for an International Monetary Fund agreement when they were not in power, Morsi and the Brotherhood now appear eager to not only gain the loan but also to borrow more than the $3.2 billion that the IMF was prepared to offer conditionally.

In this respect, Morsi and the Brotherhood seem to recognize reality. But in another important regard, they appear determined to deny it. Consider that Morsi denied sending Israeli President Shimon Peres a response to a note that Peres had written him after news of the correspondence provoked a backlash in the Brotherhood over Morsi having any such contact with Israel. What makes this particularly noteworthy is that Peres’s office did not release Morsi’s letter publicly until after checking with the Egyptians to make sure it was okay to do so. The outrage among the Brotherhood led Egypt’s president to publicly deny a fact. Similarly, consider that the Brotherhood immediately blamed the Mossad, Israel’s intelligence organization, for the Sinai attack that killed the Egyptian soldiers — something that the Brotherhood knew to be untrue.

What conclusions should be drawn about an organization that cannot admit the truth? That insists on living in its own reality? If nothing else, it’s clear that the group the Brotherhood is wedded to its ideology and cannot admit anything that might call its basic philosophy into question. But the United States and others should not accommodate the Brotherhood’s alternative reality. This is not to say that we have to agree on everything. Policy differences are understandable — but it is not acceptable to deny reality and foster a narrative and policies based on untruths and fictions.

Morsi and the Muslim Brotherhood should know this. Egypt’s president and people should also know that we are prepared to mobilize the international community, and global financial institutions, to help Egypt — but that we will only do so if Egypt’s government is prepared to play by a set of rules grounded in reality and key principles. They must respect the rights of minorities and women; they must accept political pluralism and the space for open political competition; and they must respect their international obligations, including the terms of Egypt’s peace treaty with Israel.

The record to date is not good: News reports suggest that more than 100,000 Coptic Christians have left Egypt ; there have been new efforts to intimidate the media, and Morsi has moved armored forces into the Sinai without first notifying the Israelis — a requirement of the peace treaty. The administration’s position needs to be clear: If this behavior continues, U.S. support, which will be essential for gaining international economic aid and fostering investment, will not be forthcoming. Softening or fuzzing our response at this point might be good for the Muslim Brotherhood, but it won’t be good for Egypt.