In her reporting, Ms. Cruz asserts the op/ed piece by Don Kates and Gary Mauser was "recently published."
This is true if you believe "recently published" means over six years ago.
Second, Ms. Cruz insinuates this op/ed was a "study"--it isn't, it is an opinion piece. It was published in the Harvard Journal of Law & Public Policy in 2007, which doesn't publish studies but commentary on various issues concerning the law and public policy. Thus, the article did not have to face peer-review or other scrutiny as actual studies would.
Where to start? In Luxembourg (population ~520,000), annual gun homicides rarely exceed 3. And the per capita gun homicide rate is usually around .5. In Germany (population ~82 million), gun homicides annually are about 150-200 with a per capita gun homicide rate of about .2. Statistics Pro Tip: comparing very small populations against much larger populations is very risky since, in the smaller samples, a a small movement either way will unduly skew any inference.
Ms. Cruz also glosses over the fact Germany's and Luxembourg's gun laws are very similar. She pretends Luxembourg has no guns while Germany is awash in them. In point of fact, Germany prohibits automatic firearms and requires both registration and special authorization of semi-automatic and handguns. The per capita rate of gun ownership in Germany is less than 2.5 per 100,000. The per capita rate of gun ownership in Luxembourg is 0.5 per 100,000. so, Germans tend to own guns at about 5x more than the people of Luxembourg. Yet, gun homicides are 50-150X greater in Germany. So much for gun ownership rates being "30,000 times higher than Luxembourg."
In Part 2, we will have more. Meanwhile, let's remember Ms. Cruz is part of the crowd asserting vaccinations are bad for children despite all the evidence to the contrary.