On Tuesday the S&P 500 fell 1.6% and Toronto fell 1.3%. This was apparently due to fears of U.S. involvement in the troubles in Syria.
Such world events have never factored much if at all into my investing. I have never, to my recollection, sold due to fears of such events. Instead I try to trim positions that seem fully or over-valued and I buy what seems to be good value. I try to keep some cash around to take advantage of lower prices when from time to time. In keeping with that I added a bit to my Wells Fargo position today. My inclination will be to slowly add to positions if markets decline further.