As our old pal Wretchard once said, The greatest apostasy in Marxist literature has always been to find value in the present. This is why Hillary Clinton's reported revision of the Pledge of Allegiance was so chilling. "I pledge allegiance to the America that can be." At what point do fair weather foes of their American here-and-now home turn into foul weather friends? If the answer is "never", then they have no right to blather on about their "dissent" being the highest form of patriotism. In that case, they aren't patriots, and maybe not even citizens. They're termites.
I don't include garden variety cynics in this, who served honorably but nevertheless feel that they and the nation were done dirty by those in charge. I mean the Speakers of Truth to Power, floating on their higher moral plane above those bourgeois Gaia-rapers, their fellow Americans, forever and ever and ever--come what may.
C. S. Lewis had a pretty good explanation of why patriotism is necessary. It isn't as stirring as this Robert Heinlein quote Darleen Click posted, but here 'tis:
Patriotism has, then, many faces. Those who would reject it entirely do not seem to have considered what will certainly step--has already begun to step--into its place. For a long time yet, or perhaps forever, nations will live in danger. Rulers must somehow nerve their subjects to defend them or at least to prepare for their defence. Where the sentiment of patriotism has been destroyed this can be done only by presenting every international conflict in a purely ethical light. If people will spend neither sweat nor blood for "their country" they must be made to feel that they are spending them for justice, or civilisation, or humanity. This is a step down, not up. Patriotic sentiment did not of course need to disregard ethics. Good men needed to be convinced that their country's cause was just; but it was still their country's cause, not the cause of justice as such. The difference seems to me important. I may without self-righteousness or hypocrisy think it just to defend my house by force against a burglar; but if I start pretending that I blacked his eye purely on moral grounds--wholly indifferent to the fact that the house in question was mine--I become insufferable. The pretence that when England's cause is just we are on England's side--as some neutral Don Quixote might be--for that reason alone, is equally spurious. And nonsense draws evil after it... A false transcendence is given to things which are very much of this world.
--C.S. Lewis, The Four Loves, 1960
So remember, when Islamic terrorists massacre citizens of free Western democracies, the Higher Patriot is not the unctuous peace creep who sneers: You deserved it. He's a barnacle on the ship of state. A tapeworm in the body politic. A rat in the wall. Not a patriot, and no friend of America in a time of danger.