In his latest Kiplinger’s column, former Under Secretary of State James K. Glassman says that — in spite of all of the troubling developments that have hit the economy and stock market over the past year or two — he still believes that the historical trend of the stock market producing strong long-term gains will continue.

“Perhaps some profound change has occurred in the economic and social fundamentals that underlie financial investments, making history an invalid prologue. Perhaps the United States is growing weaker and can no longer compete with China. Perhaps we are following a disastrous public-policy route. … Or perhaps the markets are looking to the future — to huge deficits or the probability of more serious terrorist attacks,” Glassman writes. “While I share such concerns, I don’t buy the notion that it’s different this time. I prefer history, for all its flaws, to my own subjective guesses about the future.”

Glassman says the past has taught us that stocks have outperformed bonds by a wide margin; stocks have been volatile over short periods but stable over long periods; and a diversified portfolio provides extra stability. Recent events have challenged those tenets, however. The decade ending Dec. 31  represented the single worst 10-year period for the stock market since 1926, when Ibbotson Associates started measuring that data, Glassman writes.

But, Glassman says to trust in the long-term track record of the stock market, which, he notes, has never been negative over a 20-year period and has delivered annual real returns around 7 percent throughout history. He recommends buying low-fee index funds or exchange-traded funds, like the Vanguard 500 Index (VFINX) or the SPDR S&P 500 ETF (SPY). In terms of individual stocks, he likes two beaten-down giants: General Electric (GE) and Berkshire Hathaway (BRK-B).