Montgomery County and Maryland are experiencing another total humiliation on the economic development front. While both have failed to attract a major new corporate headquarters this century, Fairfax County and Virginia have just beaten them once again in the high-stakes contest for yet another major defense firm HQ. This time it is Rheinmetall, the German defense giant that is experiencing off-the-charts boom times, as it is arguably the biggest winner in Germany’s push to rearm and create Europe’s largest and strongest military. It is also one of the companies producing the most equipment for Ukraine in its war with Russia. Rheinmetall has just leased 10,000-square feet at Metro Place II at 2600 Park Tower Drive in Merrifield in Fairfax County, where it will not only…..