Is it possible to try Colin Powell for the Iraq debacle?
<p>Is it possible to try Colin Powell for the Iraq debacle because he lied about WMD and that helped the Bush admin to invade Iraq based on false premises of WMD, and millions of people died as a result?</p>
<p>Please tell me about US federal law and the practical barriers to trying them.</p>

<p><strong>After the edit of the question:</strong></p>
<p>Deceased defendants are not normally put on trial.</p>
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<p><strong>Before the edit of the question:</strong></p>
<ul>
<li>The ability of the US President to start military operations is a somewhat murky issue. Congress has the power to declare wars, the President is the commander in chief, and the <a href="https://en.wikipedia.org/wiki/War_Powers_Resolution" rel="noreferrer">War Powers Resolution</a> complicates things. But this is not really an issue because Congress <a href="https://en.wikipedia.org/wiki/Authorization_for_Use_of_Military_Force_Against_Iraq_Resolution_of_2002" rel="noreferrer">approved</a> the operation. As far as <strong>domestic US law</strong>, the war was legal.</li>
<li>I'm not aware of any competent legal authority deciding on the invasion being a <a href="https://en.wikipedia.org/wiki/Crime_of_aggression" rel="noreferrer">crime of aggression</a> under <strong>international law</strong>. The practical problem here is that such trials mostly happen under UN auspices at the end of a world war, putting the defeated side on trial. The UNSC would probably be involved, and the US is a veto power.<br />
Note also that Iraq had probably violated the ceasefire agreement from 1991 ...</li>
<li>Which leaves the <strong>domestic</strong> issue of lying to the American public and especially to Congress. While perjury in a congressional hearing <em>may</em> be a crime, proving it would require a legal judgement of the state of knowledge at the time the supposed perjury happened. To a large degree, the US government deceived itself before it gave testimony, and being factually wrong is not perjury if the witness believed what he or she said.</li>
</ul>

united-states criminal-law