A nimble investor can buy almost anything on Wall Street today. With a click of your mouse, or a tap on your iPhone's touchscreen, the world is your risk-imbued oyster. Through the advent and ceaseless proliferation of ETFs, a Fool can bet long or short on virtually any region, sector, index, or strategy imaginable.

But here amid the aftershocks of our gruesome global financial crisis -- the root causes of which have hardly been curtailed -- I ask: Is a true safe haven even available for defensive-minded investors who seek to truly safeguard a portion of their hard-earned investment capital? Let's have a look.

The usual suspects
Holding a cash position within one's investment portfolio can certainly provide a valuable measure of protection against the sort of indiscriminate selling across all asset classes that pervaded global markets following the demise of Lehman Brothers in September 2008. Over time, however, these negative real interest rates that we're presently experiencing make cash a patently unattractive safe haven.

Traditionally, investors have confidently turned to U.S. Treasury bonds when discomfort arose regarding equities or other asset classes. As the Federal Reserve's second round of quantitative easing draws to a close, however, the world's largest bond fund has eschewed all exposure to U.S. government debt. In fact, PIMCO recently went a step further and built a short position in Treasuries to accompany its $73 billion cash hoard (31% of assets).

The gold and silver conundrum
While I do maintain a variable cash position to mitigate downside risk, I have personally selected gold and silver as my safe havens of choice. However, all one has to do is review the horrific sell-off in these metals in 2008 and 2009 to see that even these stalwarts of recent outperformance proved susceptible to the vagaries of indiscriminate selling. Given the sharply reduced attractiveness of U.S. Treasuries since that time, however, I consider a repeat performance of that degree of weakness extremely unlikely. Rather, the next time push comes to shove and investors run for the exits -- and unfortunately I do think it's just a matter of time -- I expect that gold and silver's true potential as ultimate safe haven assets in a world of tattered paper will gain overdue recognition among individual and institutional investors.

But risks certainly reside in gold and silver as well, and they must be fully understood. For starters, following a phenomenal run like that achieved (particularly by silver) over recent months, the specter of a sharp and abrupt near-term correction must be seen as rising in parallel. Provided one's confidence in the long-term trend remains clear, that may not present a true risk; but especially for newcomers, the risk is palpable. With respect to physical bullion, there are storage costs, storage risks, and peculiar tax implications that likewise must be taken under advisement. Popular bullion proxies like the SPDR Gold Trust (NYSE: GLD) may present another sort of risk entirely.

With those considerations in mind, my own approach to gold and silver as a safe haven play has evolved into an unconventional dance between growth-focused equity exposure to miners and explorers on the one hand, and a highly variable cash allocation designed to mitigate downside risk. Simply stated, after surveying the universe of purported safe havens, and finding few (if any) truly viable options, this equity-focused approach strikes me as a fairly reasonable compromise.

There is an unmistakable irony here, however. Although I consider my long-standing price target for $2,000 gold an entirely safe bet, the corresponding mining equity sector is fraught with a daunting array of risks all its own. As it happens, one particularly dangerous risk vector facing mining equities has stepped into the spotlight once again this week.

The geopolitics of gold and silver
Along with his stated intention to renationalize certain mining operations that had been privatized under prior administrations, Bolivian President Evo Morales issued a powerful reminder to investors that they must dutifully mitigate jurisdictional risk. The sudden announcement sent likely target Pan American Silver (Nasdaq: PAAS) scrambling to seek clarification from the Bolivian authorities with respect to its San Vicente silver mine. Such clarification is still pending.

While the move may have come as a surprise, it certainly did not come from left field. In other words, anyone with investment exposure to mining operations in Bolivia possessed a duty to themselves to recognize the nationalist tendencies of the Morales administration; particularly after Morales seized the Vinto tin smelter from Glencore International back in 2007. As it happens, Glencore is once again in Morales' crosshairs, as the remaining three mines targeted for "recovery" belong to Glencore subsidiaries. The timing is especially unfortunate for Glencore, since the company is preparing for an $11 billion IPO of its shares in London and Hong Kong.

This is, in fact, a topic of concern in multiple corners of the South American continent. Former miner Crystallex International has been essentially destroyed by the nationalization of its Las Cristinas gold mine in 2008 by Venezuela's Hugo Chavez administration. Kinross Gold (NYSE: KGC) is moving forward with a $1.1 billion investment to construct its Fruta del Norte mine in Ecuador, but as someone who lived in Ecuador and remains familiar with the political environment there -- and despite the recent reformulation of the nation's mining law -- I perceive an elevated risk that President Correa could choose a similar path with respect to some form of nationalization of key mining assets.

Because of the number of major operators and the scale of identified resources involved, the stakes are even higher in Peru. Peru recently pulled the plug on Southern Copper's (NYSE: SCCO) Tia Maria project, after a round of intense public protests that resulted in several fatalities.

Meanwhile, presidential candidate Ollanta Humala emerged victorious in an initial vote last weekend, with a runoff election scheduled for June 5. Although both remaining candidates have proposed imposing a tax on miners operating in Peru, Humala is widely perceived as a wild card who could potentially pursue a more disruptive approach. Peru is a very significant global supplier of copper, gold, and base metals, and major players from BHP Billiton (NYSE: BHP) to Freeport-McMoRan Copper & Gold (NYSE: FCX) are no doubt tracking these developments with some concern. I recommend that Fools holding investment exposure to mining operations in Peru maintain similar vigilance. Having just recently acquired a promising copper property in Peru, miner HudBay Minerals (NYSE: HBM) also has a lot at stake.

In the final analysis, it may ring true that this particular period of the world's financial history offered investors little in the way of truly reliable and effective safe havens. Among the array of imperfect options, I consider gold and silver mining equities -- particularly when coupled with a steadily expanding cash position -- as a reasonably attractive alternative. By remaining diligent in the area of risk assessment as it relates to such assets, I believe investors can harness the long-term continuity of gold and silver price appreciation to effectively preserve capital and grow capital with a single precious strategy.