How can a man be charged with both first degree murder and second degree murder simultaneously for the murder of the same person?

Second degree murder is called a lesser included offense of the first degree murder charge.

That means that if the prosecution charges and proves the first degree murder charge it has been deemed to prove the second degree murder charge and the more serious charge applies in terms of punishment.

If the prosecution charges both first degree murder and second degree murder, it is putting the Defendant on notice that if the jury fails to convict on first degree murder, it will be asking for a conviction of second degree murder as an alternative.

It's a safety net for the District Attorney. It gives him the ability to allow a defendant to plead guilty to the lesser charge, which puts another win on his record without having to work too hard for it. It also gives a jury another charge to consider if they think first degree murder hasn't been proven beyond a reasonable doubt. Either way, the D.A. comes out a winner and the defendant goes away for a long time.

Strictly procedural. You can charge the maximum charge and all lesser included charges. If you don’t charge it in some jurisdictions, it’s not on the table later.

Knowing this, some prosecutors deliberately omit lesser charges in an attempt to force a jury into the position of finding the harshest verdict or completely releasing the defendant. Risky -been known to backfire- but fucking ballsy move.

The truth is, a given set of facts is open to a number of interpretation. That’s the jury’s function - to sort the facts out.

They include the lesser charge so that when it goes to the jury they can convict them on the lower charge in case there isn’t enough evidence to convict them on the more severe charge. For example, an expert witness testifies and casts doubt as to how the victim died. This doubt makes it so the jury may think the death was not per-mediated, something that is required for first degree murder, and instead may have been accidental. Well now the prosecutor can ask the jury to consider second degree murder as well.

Yes, deliberately planning on killing a pregnant woman.

More commonly, that would be a murder and manslaughter charge, but in some jurisdictions, it could be any combination.

Yes, in Washington. However, he can’t be convicted of both. Thus, generally speaking, a defendant could be charged in the alternative.