Fun fact! Basically every developed country in the world is legally obligated to provide 0.7% of GNP in official government aid to poor countries to help them escape poverty. Who knew!?!
Let me explain. Aside from the United States and Botswana, every reasonable country (i.e. every country that is not a dictatorship, has more than five citizens, or isn't an otherwise failed state) has signed the International Covenant on Economic Social and Cultural Rights (ICESCR). Article 2(1) of the ICESCR commits states to "take steps, individually and through international assistance and cooperation, especially economic and technical" to help fulfill the economic rights of poor people around the world. Now the ICESCR is a binding international agreement, but unsurprisingly, there's a lot of disagreement about what it specifically requires and what states are actually obliged to do. That being said, a very very authoritative international legal scholar holds that "there is broad agreement that the Covenant imposes at least some extraterritorial obligations...."
The most authoritative legal interpretations of these extraterritorial obligations hold that developed countries are required to give 0.7% of their GNP in "official development assistance." Where did they get that magic number? Starting in 1970, a half-dozen UN Resolutions have been passed that set and continually reaffirm this number as the minimum level that states need to reach. Most recently, in 2008, the UN enshrined this target again and the EU committed to bring itself in line with the standard by 2015. In 2013, the UK increase it's assistance to the 0.7% minimum to comply with its international obligations.
Why does this matter? At the very least, it might be something good to keep in mind in our advocacy. We can shame our countries for failing to comply with the most authoritative statements of international law, and their explicit promises to reach the 0.7% target. But maybe we can do more. Maybe someone can bring a case and force them to reach their commitment to 0.7%. I'm not sure what that would look like, or if it is possible to even bring such a case, but it definitely seems worth looking into, maybe even for the PR value alone. That's because a quick glance tells me that the EU would have to essentially double its aid spending. Germany and France, for example, are only around the .40% mark (at least as of 2013).
There may be other interesting opportunities lurking in here. The extraterritorial obligations also prohibit countries from trade policies that hurt the foreign poor (subsidies, immigration etc.). I'm going to keep digging around here.
(Edit- I have retracted the following text because it is just wrong and misleading:
"The European Court of Human Rights and several national courts of EU countries, are known for vigorously enforcing international obligations (at least by global standards). EU countries regularly comply with court orders to fulfill their obligations under the ICESCR. These court orders frequently require governments to change their budgets to meet the economic and social rights of their residents."
I was actually thinking of a non-binding European decision-making body that is very influential but whose decisions are not mandatory. Additionally this body does not appear to rule on extraterritorial obligations since the European human rights system does not seem to include such obligations in their body of law. I have explained more in the comments below.)
ODI as percentage of GNI:
Super authoritative commentary to super authoritative legal opinion regarding developed states' extraterritorial obligations:
http://www.lse.ac.uk/humanRights/documents/2012/HRQMaastricht.pdf (p. 1151)
2008 UN Resolution where they reaffirmed this obligation and EU said they'd give .7% of total GNP by 2015
http://daccess-dds-ny.un.org/doc/UNDOC/GEN/N08/485/13/PDF/N0848513.pdf?OpenElement (p. 12)