[Redcloak]

The correct phrase is, "has some reasonable relationship to the preservation or efficiency of a well regulated militia".

Remember that the complete phrase is...

In the absence of any evidence tending to show that possession or use of a 'shotgun having a barrel of less than eighteen inches in length' at this time has some reasonable relationship to the preservation or efficiency of a well regulated militia, we cannot say that the Second Amendment guarantees the right to keep and bear such an instrument.

The evidence was "absent" because it was never presented. Only the Federal Government's case was presented before the Court. Miller had fled (or died by some reports) before the case was heard. His side wasn't represented. Had Miller's attorneys been present, they may have shown that a sawed-off shotgun is indeed a useful militia weapon.

[robertpaulsen]

"The evidence was "absent" because it was never presented."

Correct.

Why was the U.S. Supreme Court interested in "some reasonable relationship to the preservation or efficiency of a well regulated militia"?

"they may have shown that a sawed-off shotgun is indeed a useful militia weapon."

Perhaps they could have. Who were Miller's attorneys going to use to testify in court as to whether or not a weapon was suitable for a state's Militia?

Since this decision affects a state Militia, shouldn't each individual state be the one to decide which weapons their Militia will use? Shouldn't the state be testifying? Aren't these the weapons which the federal government "shall not infringe"?

What if Mr. Miller's weapon didn't qualify as a Militia-type weapon? What would have happened?

[takenoprisoner]

While the 2nd Amendment does not define or limit arms, it is inferred to mean whatever arms are available. And not only does the 2nd Amendment not define the sort of arms, it also does not restrict modifying of available arms.

Meanwhile, I don't think other milita members will give a rats ass what weapon I bring to fight so long as I show up ready to fight.

[zeugma]

Had Miller's attorneys been present, they may have shown that a sawed-off shotgun is indeed a useful militia weapon.

Would have. They were extensively used in WWI. Commonly known as 'trench guns'.