I have asked MIDA to develop some suggestions, which I subseqently reviewed, about bringing our Federal buildings up to a more secure standard, such as the one now used in the US as described at
http://www.ccb.org/docs/GSAMAN/mfacstd1.pdf (don't download it for fun as it is a 40 MB document covering every aspect, many beyond security). There are a variety of potential threats, with car/truck bombs and weapons being smuggled in being the two on the top of the list, but missile (or mortar or RPG) and chemical/biological threats should be considered. Obviously, it is easier to build in appropriate protection when the building is being designed than to retrofit it later. For new construction, bringing them up to a higher security standard adds about 4% to the cost of the typical building. The main protection against car and truck bombs is keeping the explosion at some distance from the side of the building and hardening the building. The former is more practical for retrofits, so we should pursue that first. Both are one time costs, requiring little or no ongoing expenditure. For weapons being smuggled in, the best protection is metal detector and x-ray machines, with additional security personnel to man them. This is a modest capital cost, but has higher on-going costs as it is labour intensive.
Hardening the building also offers protection against missile threats, although the parts of a building needed to be hardened can be different. Protection against Chemical and biological agents is primarily through altering the HVAC (Heating, Ventilation, & Air Conditioning) systems.
My staff estimates that there are 155 Federal buildings through out the UPE that should have higher priority. This includes buildings within the rings of steel, but as security works best in layers, I wouldn't want to exclude them. The cost per building vary widely, but an initial estimate for them averages just over three million ducats per building or about a half a billion ducats for increasing the set-backs, slight hardening, and security scanning equipment. This should be added to the budget, at roughly 100 million per ministry, or it could be proposed as part of an omnibus anti-terror bill. Pick a number that you think would pass and we can come up with the details of how best to spend it, between this, more FLEA agents, etc.