A couple of weeks ago, my Foolish colleague, Rich Duprey, penned a column in this space criticizing Congress's ill-considered torpedoing of the Dubai Ports deal. Today, I'm here to follow up with a collateral damage report.

As you probably recall, Dubai Ports (DP) is based in the United Arab Emirates. When DP bought Britain's Peninsular and Oriental (P&O), one effect of the concentration would have been to put an Arab company in charge of managing the operations of several U.S. port facilities. That idea didn't sit well with many of our elected officials in both camps or with the American people, and P&O ultimately agreed to sell off its U.S. port operations to an American firm yet to be chosen.

One criticism leveled at the DP deal was that it was approved too quickly. The Committee on Foreign Investment in the U.S. (CFIUS) failed to subject DP to the optional extra 45-day review process before approving its acquisition of P&O's U.S. operations. Last week, we learned that even going that extra step offers no guarantees. On Friday, Israeli computer security firm Check Point Software (NASDAQ:CHKP) announced that it was withdrawing its $225 million bid to acquire Columbia, Md.-based Sourcefire, a private provider of network security services, after the CFIUS review was elevated to "a more serious investigative stage."

Never mind that. With the possible exception of the Holy See, there's no country in the world less likely to attack the U.S. or aid terrorists than Israel. Congress is on the warpath, the Bush Administration is running scared, and with less than a month intervening between the DP fiasco and the deadline for approving Check Point's acquisition, the latter deal was doomed.

But what, you may ask, does all this mean for individual investors?

It's a matter of simple economics -- supply and demand. If you hold supply of a product constant and depress demand, the product's price will fall. Our national concern to keep "foreign" firms from buying "our" firms decreases demand for a product -- U.S. companies. So by reducing the number of potential bidders for our companies, we inevitably lower the winning bid price.

Fortunately, because Sourcefire is privately owned, this particular incident won't hurt investors' wallets. But think back to the similar situation we saw last year, when China's CNOOC (NYSE:CEO) wanted to buy U.S.-based Unocal. When concerned members of Congress scuttled that bid, Unocal shareholders lost out on $1.5 billion -- the difference between CNOOC's $18.5 billion offer and the $17 billion bid by Chevron (NYSE:CVX) that eventually won the day.

Jingoism comes at a cost, folks. With every CNOOC, Dubai Ports, and Check Point that we shut out of our markets, the value of our shareholdings erodes a little more.

Read more about the CNOOC and Dubai Ports deals in:

Fool contributor Rich Smith does not own shares of any company named above.