Germany's top court ruled Tuesday that a key crisis fighting tool of the European Central Bank complies with German national law, throwing out objections by a group of eurosceptics. 

The constitutional court ruled that the ECB's 2012 bond-buying plan called Outright Monetary Transactions (OMT) complies with German law.

OMT -- though never actually used -- was part of ECB's President Mario Draghi's landmark promise to do "whatever it takes" to save the battered euro at the height of the crisis in 2012.