How would the U.S. react to a Chinese invasion of neighbor?

[Reality Check]

How would the U.S. react to a Chinese invasion of a neighbor?

Some Chinese military planners believe that Americans will "run like rabbits" and not honor its mutual defense treaties, if China invaded one of its neighbors. A lot of commenters believe the same thing:
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I expressed the opinion that "President Obama would not have any choice if Congress declared war, which might happen within hours of any Chinese attack." One reader responded:

"First, yes he would. He could dither on the deployments the way France and the U.K. did after Hitler seized Bohemia and Moravia and declared Slovakia a Protectorate, then dithered some more when Hitler declared war on Poland, launching a mighty Sitzkrieg offensive in the Pacific while saving the Blitzkrieg for the media and stump circuit.

In the face of that, all Congress could do is impeach him, even while an attempt is made to repeal the 22nd Amendment so he can do nothing for even more [years].

Second, what if a declaration of war passes the House but not the Senate? Never mind the Chamberlain in the White House, Harry Reid could play his own version of Neville, and no war resolution would ever reach the floor of the Senate.

What exactly would happen if Congress "couldn't" decide?"

Dithering would be a high-risk political strategy for the President and a Democratic Senate. When Neville Chamberlain promised "Peace in our time" after meeting with Hitler, he was doing something that seemed perfectly reasonable on that day. And yet, Chamberlain has been damned by history as the man who appeased Adolf Hitler. President Obama would risk being damned as a modern day Neville Chamberlain who appeased the Chinese.

[Reality Check]

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Obama's view of his place in history is a very interesting political consideration to inject into this discussion.

Obama appears to view himself as an instrument of fundamental change within the United States.

A foreign war on his watch could jeopardize that, and it would be something he would seek to avoid.

On the other hand, Obama appears to truly believe he has the correct answer to almost every question, which means he might engage in what he believed would be a very short, very one-sided military action, only to find his crystal ball regarding what China could do, or would do, was simply 100% wrong.

More likely however, Obama would seek to avoid nuclear war at all costs. This is likely what China would have to be counting on to launch a war in the next couple of years.

Obama's often stated arms control agenda indicates that he shares the very dangerous world view that using any significant number of nuclear weapons would destroy the world, so therefore they will never be used. This of course is pure fiction, but a majority of politicians in the Democratic Party appear to believe this as an article of Religious Faith.

Should China convince Obama that China was "crazy enough" ( in Obama's World View ) to use nuclear weapons to subdue say Vietnam or any non-nuclear neighbor that launched a military attack on China or China's expeditionary military forces ( regardless of the provocation or justification for such an attack on China ). Such convincing could take the form of nuking something, Like say a Vietnamese army and/or a city in Vietnam...

Then Obama's world view on nuclear weapons would lead him to avoid, at all costs, being the President who elected nuclear war. Obama would fear this far more than he would fear going down in history as the President who attempted to achieve "Peace in our Time" and was later dragged into war.

Remember, unlike England, the leader in the United States would remain in power, and have a second chance to go to war if it turned out China behaved like the Germans after the Czechoslovakia compromise that brought "Peace in Our Time". A second chance the English leader did not have without a guaranteed four year term. This is a major difference in how Obama would be viewed by history, Obama would be both the President who tried to avoid war and then was dragged into it, even if he chose "Peace in Our Time" after the first War started by China.

[Reality Check]

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All the Above assumes that Obama even cares about such historical things in the conventional terms we believe Presidents do.

Obama may see himself as a transformational figure such as Lenin or Mao, in which case he would care nothing at all about a "Peace in Our Time" label.