Amid calls for Europe to rearm, competing ideas are circulating around how to ensure European nations can take on Russia in a possible future war without U.S. backing. While the idea of a rearmament bank may carry some appeal, it’s less clear that there’s any new money for what is likely to be a very expensive enterprise.

The European Commission recently unveiled €800 billion ($876 billion) plan to REARM. The plan essentially involves imposing a huge hike in defense spending on every member state. Some €650 billion ($712 billion) of the funds would come from each of the 27 members increasing defense spending on average by 1.5% of GDP on top of current levels.

It’s hard to imagine that such an increase would be politically palatable given that many European governments are highly in debt. For example, France would need to increase its military spending by almost $47 billion each year when its debt stands already at 113% of GDP. Likewise Italy, the EU’s third largest defense power, would have to increase spending by $34.7 billion each year with its current debt at 136% of GDP.

So, European countries are scrambling to seek elegant ways to boost defense spending, including off-balance sheet. One idea that has emerged recently has been creating a Rearmament Bank (also known as a Defence Security and Resilience Bank). It would be designed to tap private investment to support development of defense capabilities.