F.L. I sold most of my history books about 20 years ago, when I started law school. But the following dates are significant.
7/31/14 Germany learns that Russia is mobilizing. Germany sends an ultimatum to Russia, to stop. Germany asks France to state whether it will support Russia. France answers ambiguously.
8/1/14 German government receives a message from England, offering to guaranty French neutrality. Wilhelm II tries to order Generalstabschef Moltke to mobilize only in the East, against Russia. Moltke responds that he cannot accept responsibility for such a mobilization. Germany has no plans for such an eventuality.
8/2/14 Germany sends an ultimatum to Belgium, demanding a statement that Germany will be given free passage to invade France.
8/3/14 Germany declares war on France. Grey addresses Parliament, stating that violation of Belgian neutrality will mean war. This was not only pursuant to treaty, but also because England considered occupation of Belgium a direct threat.
8/4/14 English ultimatum to Germany.

I haven't bothered to look up the date on which England declared war. The very existence of the Schlieffen Plan, and the fact that there were no alternatives, assured that England and France would be involved. Of course, this does not mean that Germany is "guilty" for the War. It means that its reliance on the Schlieffen Plan was disastrous. The fact that the Plan existed, and that there were no alternatives, had its roots in domestic political considerations. Very similar to the considerations that today determine American military and foreign policy today.

Western involvement was only "inevitable" because of the idea that a prolonged war, which would have resulted had Germany moved only against Russia, was intolerable, so that no other plans could be made. The government believed that a long war would be fatal to the monarchy, and it appears they had a point there. But that had nothing to do with "national interest." And incidentally, an important reason the Schlieffen Plan failed is because the German Army was smaller than it should have been. And this in turn was so because further enlargement would have required permitting "politically unreliable" (liberal) people to serve in the officers' corps. Ludendorff, who demanded a larger army, was sent off to a beat in the sticks as a result.

More to the point, people should take a look at the link provided by Don Firth. And here is another interesting link, to a site provided by the CATO INSTITUTE. And another to BUSINESS WEEK. And the Atlanta Journal Constitution. And the National Security Strategy of the United States of America. And finally, a link to FOX NEWS. All of which illustrate the parallel people are pointing out with the past events referred to. And which show things I had not been fully aware of. Doubtless McGrath knows all about it, but I hadn't.