This is an unserious proposal. Germany spends about 1.5 percent of its GDP(*) on defence, much of it wasted, and increasing it to even 2 percent has involved painful and extended political wrangling. If the country collectively cannot find the will to tweak its budget to fund a modest increase in defence spending, it is not going to countenance universal conscription.
This is PATENTLY wrong. It's 1.49% of GDP, not budget.
Defense budget is 10.9% of the governments budget, it's the second largest budgeted item after social wellfare and in front of infrastructure (which is crumbling) and debt. To increase it to 2% of gross domestic product means spending an additional amount equal to the entire budget for education and research.
