Problem: The European Central Bank had stepped up the buying of member nations debt. In response to the crisis of 2010, some proposals have surfaced for a collective European bond issue that would allow the central bank to purchase a European version of US Treasury bills. To make European sovereign debt assets more similar to a US Treasury, a collective guarantee of the member states' solvency would be necessary.[b] But the German government has resisted this proposal, and other analyses indicate that "the sickness of the euro" is due to the linkage between sovereign debt and failing national banking systems. If the European central bank were to deal directly with failing banking systems sovereign debt would not look as leveraged relative to national income in the financially weaker member states.
Why did propsals about making the European sovereign debt assets more like the US Treasury?
The answer is the following: the crisis of 2010

Problem: In the north, the Republic of Novgorod prospered because it controlled trade routes from the River Volga to the Baltic Sea. As Kievan Rus' declined, Novgorod became more independent. A local oligarchy ruled Novgorod; major government decisions were made by a town assembly, which also elected a prince as the city's military leader. In the 12th century, Novgorod acquired its own archbishop Ilya in 1169, a sign of increased importance and political independence, while about 30 years prior to that in 1136 in Novgorod was established a republican form of government - elective monarchy. Since then Novgorod enjoyed a wide degree of autonomy although being closely associated with the Kievan Rus.
What happened to Novgorod when Kievan Rus began to decline?
The answer is the following: became more independent

Problem: This means that a 5% reduction in operating voltage will more than double the life of the bulb, at the expense of reducing its light output by about 16%. This may be a very acceptable trade off for a light bulb that is in a difficult-to-access location (for example, traffic lights or fixtures hung from high ceilings). Long-life bulbs take advantage of this trade-off. Since the value of the electric power they consume is much more than the value of the lamp, general service lamps emphasize efficiency over long operating life. The objective is to minimize the cost of light, not the cost of lamps. Early bulbs had a life of up to 2500 hours, but in 1924 a cartel agreed to limit life to 1000 hours. When this was exposed in 1953, General Electric and other leading American manufacturers were banned from limiting the life.
What was the artificially low limit on bulb life placed by the cartel?
The answer is the following: 1000 hours

Problem: Treaties can be loosely compared to contracts: both are means of willing parties assuming obligations among themselves, and a party to either that fails to live up to their obligations can be held liable under international law.
What must a party to a treaty do to prevent being held liable under international law?
The answer is the following:
live up to their obligations