Three days after President Trump signed an executive order sharply curtailing immigration and the rights of refugees, questions about its reach and legality are increasingly focusing on the order’s uncertainty.

By circumventing normal practices for formulating policies and their execution, the White House has created still-swirling confusion about whom the order targets and how it will be enforced. There is also ambiguity about the legality of the order, which the White House calls extreme vetting but which critics call a Muslim ban, and about how court challenges, already underway, will proceed.

For many abroad, the ban raised questions about how an American president could undertake such an action suddenly and unilaterally, seemingly unfettered by checks and balances. The order’s apparent breaches with usual protocol over how policy is made, and potentially with the law, are already creating major problems in its enforcement.

Why has the order created such disarray?

The order targets three groups: refugees from any country, who are blocked from entering the United States for the next 120 days; refugees from Syria, who are barred indefinitely; and citizens from seven Muslim-majority countries, who are barred from entering the United States for at least 90 days. Those countries are Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen.