The practice and theory of diplomatic law have not developed generally accepted criteria for refusing agrement. However, three groups of general criteria can be separated: the first relates to the candidate himself, his past and his attitude towards the host country; the second is due to the state of relations between the two countries and therefore does not directly concern the person of the candidate for the position of Head of Mission. Thus, the United Kingdom refused to accept the clergymen as representatives of the Holy See. The same is true for countries that do not want to recognize a state or government or do not want a person to be accredited simultaneously in certain countries, such as Italy. B and the Vatican do not agree that the same person should represent a state simultaneously in Italy and the Holy See. The third reason for the attacker`s refusal may be the question of the candidate`s nationality, particularly if he or she has the nationality of the host state. In the past, this problem has been solved differently. Some countries agreed, others did not, or exceptionally, as in 1868, when the United States refused to accept a Chinese ambassador of American nationality. In 1945, however, the U.S.
government agreed to appoint Oskar Lange as ambassador of the Polish provisional government, even though he was a U.S. citizen at the time. However, in international practice, the principle of non-aggressiveness prevails for its citizens and, to a lesser extent, for naturalized expatriates. An agrement is also necessary when an MP is promoted to the ambassador class. Such situations often occurred in the post-war period, when many mEs were brought to the level of embassies. The same applies to situations where a delegation that does not have diplomatic mission status is transformed into a regular embassy or embassy. Under modern diplomatic law, every state has the right to refuse an aggressor without having to justify it. Sometimes a state that does not intend to grant an aggressor does not do so directly, but waits for a response, in the hope that the sending state will draw conclusions and nominate a new candidate. In the 1961 Vienna Convention, Article 4, paragraph 2, states that “the host state is not required to state the reasons for the aggressor`s refusal to the State of origin.” In the past, some countries, such as the United States, the United Kingdom and France, have often asked for explanations of rejection. However, the principle is that the host Member State may, depending on its choice and willingness, refuse to grant the aggressor and avoid justifying such a refusal, although in practice the reasons for such refusal are generally indicated for reasons of future relations between the two States and for reasons of courtesy.
Such reasons must obviously be important, such as the candidate`s hostile attitude as ambassador to the host country, which is a shame for the past. In the past, there have been cases where some countries have refused to become aggressive, for example. B for female or racial reasons (Charles XII, King of Sweden, did not agree to accept as an MP the favourite of the King of Poland August II, Countess of Aurora of Koenigsmark, famous for her beauty and intelligence). The refusal may also be due to the non-authorization of the government or the sending state, de facto or iure. It is always to be expected that the refusal of the aggressor, which is a serious step, can have a negative impact on the atmosphere of relations between the two countries.