As far as that goes, Lincoln and FDR overstepped their bounds, yet they are considered great Presidents. Had they not acted as they did, slavery would have continued in the South into the 20th Century and German would be the preferred language in Paris, London, and Moscow in the 21st Century. I am sure the Cold Warriors such as the Dulles brothers, Henry Kissinger, William Colby, etc., bent or broke a few legal limits in protecting America's interests overseas. So did Oliver North and Admiral Poindexter in aiding the Nicaraguan Contras. It is hard to argue that riding the world of such enemies of America as Mossadegh in Iran, Allende in Chile, and Ortega in Nicaragua was not in the best interests of our country.
As stated previously, the Constitution is not a suicide pact. Better to act than to let thousands of people die needlessly due to ineffective state and local leadership.
This seems a lot like the old "husband's maxim": it's better to ask for forgiveness than permission.
imagine what Sharpton and the MSM would be saying now, if in the first 24 hours of this crisis, Bush had dismissed the governors rolein manitaining civil order and started flying Cobra gunship over new orleans to gun down the looters. just imagine that, you think the coverage is biased now, imagine if he had done that.
This is summarized neatly by Emerson's famous aphorism: "A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines."