The agreement helps both governments better manage access to the refugee system in each country for people crossing the land border between Canada and the United States. The two countries signed the agreement on 5 December 2002 and came into force on 29 December 2004. For all other countries that could be classified as safe third countries in the future, the Trump administration is methodically building the U.S. asylum system to reduce immigration to the United States. One of the most devastating changes introduced by the government is the negotiation of agreements with Central American countries that require asylum seekers transiting through a country to seek refuge there first. Critics say Trump`s proposed trump agreements do not meet those standards. They claim that Guatemala and Mexico cannot afford to process so many asylum applications and report warnings from the Foreign Ministry that asylum seekers are threatened with violence in both countries. Many also say that such agreements do not address the causes that drive people to flee and may only encourage them to find alternative routes to the United States. Mexico. Mexico has refused to sign an agreement on safe third countries and officials say they have already helped reduce migration to the United States. Since January, the Trump administration has sent many asylum seekers to Mexico while their cases are processed.
In an agreement signed in June under customs pressure, Mexico agreed to take in more asylum seekers and strengthen enforcement of its southern border with Guatemala. The Safe Third Country Agreement applies to refugee claimants who wish to travel to Canada or the United States at Canada-U.S. border crossings (including rail). It also applies to airports where a person seeking protection in Country B has not been identified as a refugee in Country A and is transiting in Country A as part of his removal. The agreement on the security of third-country nationals is not a treaty requiring congressional approval and can be signed and adopted unilaterally by the President. This has allowed the Trump administration to bypass Congress and the courts, impose new restrictions on asylum seekers, limit migration to the United States, and re-deliver the obligation to take asylum seekers to other countries to the United States. Conventions on safe third-country nationals are not explicitly mentioned in the 1951 Refugee Convention or the 1967 Protocol on the Status of Refugees. Rather, their legitimacy derives from Article 31 of the 1951 Convention, which states that a refugee should not be punished for illegal entry into a country if he arrives directly from a country where he is threatened.
The Office of the United Nations High Commissioner for Refugees (UNHCR) has itself warned against over-interpreting safe third country agreements, although it acknowledges that they may be acceptable in certain circumstances.  Such ambiguities have prompted some Canadian legal experts to question the legality of the Canada-U.S. safe third country agreement.  If all these agreements are implemented as planned, tens of thousands of asylum seekers will travel to the United States.