Earlier this year, a scientist named Muntaser Ibrahim was arrested and imprisoned in Sudan. A respected geneticist, Ibrahim was protesting against the government of Omar al-Bashir, who took power 30 years ago in a military coup. Other Sudanese protesters have been killed by security forces during recent demonstrations. The unrest was sparked by an economic crisis and the resulting hardships faced by many Sudanese people.

People like Muntaser Ibrahim are called political prisoners. What happened to him is not unusual. In fact, the same pattern is very common around the world. People who publicly oppose a ruling government, or object to some of its policies, are often locked up for speaking out. Sometimes movement leaders are targeted; in other cases simply joining a march or signing a letter of protest can lead to arrest. Some examples of well-known political prisoners include Zehra Doğan, a Kurdish artist who was jailed by the Turkish government for a painting she created; members of the anti-Putin Russian punk band Pussy Riot, who were imprisoned after staging a protest in a church; and Iranian attorney Nasrin Sotoudeh, who was recently sentenced to 38 years in prison—and 148 lashes—for defending dissidents.

Muntaser Ibrahim’s friends and colleagues have issued a statement requesting international support for his release. Their goal is to raise awareness of Ibrahim’s situation. That is because in some high-profile cases, political prisoners receive public support from petitions, celebrities, and human rights organizations like Amnesty International. Sometimes other nations’ governments, or the United Nations, will apply pressure on behalf of political prisoners. For instance, the United States has sometimes tried to use trade policy to influence human rights policies in China, where activists and journalists often face arrest if they criticize the government.

Freedom for political prisoners around the world is a positive goal most people can agree on, but a number of factors make achieving this complicated and difficult. First, who qualifies as a political prisoner? Not everyone agrees on the definition. For instance, some people break the law because of their beliefs. During the American civil rights movement, black people in southern states committed civil disobedience, breaking racist laws to show that discrimination was wrong. They were technically arrested for breaking laws, but they were often then brutally mistreated by police or given very harsh sentences because of their political beliefs. Most people today would agree that being targeted in this way made them political prisoners, but local authorities at the time would have denied this. The well-known Chinese artist Ai Weiwei was prosecuted for a variety of crimes, but the people and groups supporting him insisted that these charges were just a pretense for attacking Ai due to his politics.

What if someone makes a political statement that includes inciting violence? In the 1960s, Nelson Mandela worked with groups that committed violent acts against the apartheid regime in South Africa. He was even labeled a terrorist by some nations, including the United States. Yet he was also one of the most famous political prisoners in history, and if you ask most people why he spent decades in jail, they will likely say for his political beliefs. While the movement to free Nelson Mandela was strong and international, just being a political prisoner does not automatically indicate that somebody should be freed. To address this issue, Amnesty International differentiates between “prisoners of conscience” who are punished specifically for their non-violent beliefs (Muntaser Ibrahim is a good example) and other political prisoners who might have advocated or even committed violence. Therefore Amnesty International sometimes just advocates for respecting the rights of political prisoners rather than for releasing them.

Should it matter what someone’s specific political beliefs are, when we are defining who is a political prisoner and whether their rights are being violated? Most people might be sympathetic to somebody jailed for advocating equality, but what about somebody with beliefs we don't like? In Germany, it is illegal to deny that the Holocaust happened, or to give a Nazi salute. Are Germans who get arrested for breaking these laws political prisoners? If they are, then just being a political prisoner does not automatically guarantee someone our sympathy. If they are not, then who decides which beliefs determine someone’s status as a political prisoner or not?

Even when the facts seem clear, international politics can still interfere with seeking freedom or justice for political prisoners. The United Nations has issued numerous declarations and resolutions defining political freedom and proper treatment of prisoners. Howevereven documents like the International Covenant on Civil and Political Rights allow exceptions to free speech if someone attacks “the rights or reputations of others” or endangers national security or “public order.” This makes it easy for a country like Iran to accuse people like Nasrin Sotoudeh of “spreading propaganda” and “conspiring to harm state security” in order to make her arrest and sentencing seem legitimate.

This can also provide cover for powerful countries that might have leverage but are reluctant to condemn their own allies for human rights abuses. China has often defended North Korea when that country’s regime was criticized for mistreating its citizens. The United States has often defended Israel when the rest of the world almost unanimously condemned Israel’s treatment of Palestinians. Russia has defended the Assad regime in Syria. With political favoritism preventing international consensus, it is hard to enforce a consistent standard. As a result, most political prisoners remain at the mercy of their governments. With so many victims of injustice around the world, focusing international pressure on a single case is nearly impossible. This is bad news for people like Muntaser Ibrahim, whose family does not even know where he is being held.

In the end, the only reliable way to protect people from becoming political prisoners is for governments to be accountable to their people. Since national sovereignty limits how much outside forces can help (and powerful nations’ attempts at regime change and nation building so often fail) it is ultimately up to the people of each country to create a government that represents and respects its people, including their right to political expression and action. This does not mean that petitions, diplomacy, or groups like Amnesty International are useless. These forces can help lead to the release of political prisoners, and to better treatment for oppressed groups. But until powerful members of the international community can put aside self-interest and unify to protect universal rights, both political prisoners and whole nations struggling under oppressive regimes will be on their own.