E/CN.4/2006/73 page 13 59. In addition, certain particularities of some host countries’ immigration policies and practices that can render migrants especially vulnerable to abuse have also been highlighted. Such policies and practices include the confiscation of a migrant’s identity documents by employers, sometimes with the apparent complicity of government officials who confiscate such documents at the time of entry and hand them over to employers; the existence of “sponsorship” systems where migrants are not allowed to change employers so that the legality of their stay in a specific country depends entirely on these employers; lack of monitoring of places of work and private recruitment agencies; placing certain categories of migrants such as domestic migrant workers outside the protection of the law; and lack of support for migrants wishing to complain of abuse. Particular difficulties in instantiating and pursuing legal action are faced by migrants who have returned to their home countries. 60. As far as sending countries are concerned, the adoption of comprehensive programmes of protection for their migrant nationals is an important development. Such action is often carried out by various government ministries and agencies and often through a country’s consular services. The issue of protection in general and, more specifically, that of consular protection is a theme that also deserves further consideration and examination as such practices can provide important examples and guidance to Governments seeking to protect migrants from violations and abuse. 61. In situations of both regular and irregular migration, legal or practical restrictions on migrants’ participation in unions are a key factor in abuses suffered in the labour market. For this reason, this is a fundamental issue that was highlighted by the Special Rapporteur in his report to the General Assembly. 62. Likewise, discrimination and anti-migrant ideology, which can be evidenced by the existence of racist crimes, police profiling, reports in the media and declarations by political figures, is a factor that affects all migrants, whether they be regular or irregular, temporary or permanent. Finally, as with other human rights violations, impunity for abuses is one of the principal elements in the persistence of human rights violations. 2. Underlying factors and specific situations 63. In order to adopt effective action against violations of migrants’ human rights, it is essential to consider the different aspects of existing violations, including the underlying factors leading to such violations. Today, many of the problems of migration take place in the private sphere, so that the State is responsible for a failure to act in legislating and enforcing the law. Thus, the actions of smugglers and traffickers, of private employment agencies and of abusive employers are primarily attributable to private individuals or companies, though the State retains responsibility for lack of due diligence in enforcing the rights of migrants. Moreover, in cases concerning particularly vulnerable persons, such as children, the State has additional obligations to ensure protection. 64. Nevertheless, the State is directly responsible for many difficult and sensitive issues linked to migration, such as action taken by State agents in the course of border control, arrest, detention and guaranteeing fair hearings; trial procedures for migrants, whether in administrative