Ever since the Civil War, this amendment has been more and more marginalized. In three cases ruled on today by the Supreme Court, it has effectively been thrown out the window. The basics of this amendment say that any power the Constitution doesn't give to the federal government, or doesn't explicitly ban, belongs to the states and the people. This gave the states final word on a large number of topics, but kept them from removing civil rights from the people.
Slowly this has been eroded. Recent laws like this include the CAN-SPAM act, which overruled much stronger state based anti-spam laws, throwing out lawsuits that were in court at the time. There are also the medical marijuana laws in California and Oregon that are completely overruled by FDA and other federal blanket bans on the use of it. Today, using the same premise as was used in these cases, the Supreme Court overturned lower court rulings against medical equipment providers. These rulings were prosecuted in state courts on state laws that were more restrictive than FDA and related rules. These infractions caused serious damages to the litigants. The Supreme Court decided that the lesser restrictions provided by the federal government (you know, the FDA that took 5 years to remove heart attack inducing drugs from the market) overrule state laws and indemnify the corporations.
This is a clear violation of the tenth amendment. The states have a very clear law on this and the Constitution doesn't cover this area of law. If there were no state laws and the federal government did have one, the federal law would hold sway. But the Constitution is very clear whose laws take precedence. Our laws and courts should not take away citizens' rights, yet time and again under this administration we have suffered. It is time for a real change.