Trade War, what was it good for?

So is that the end of The Trade War That Wasn't? When US Treasury Secretary Steve Mnuchin emerged from talks with a Chinese trade delegation with a smile on his face, the business world breathed a sigh of relief.

The trade war was "on hold" Mnuchin said. "There never was a trade war," he added. "What I would really have said is this has been a trade dispute all along."

The market lapped that up. The Dow Jones index rose 298 points on the news to close above 25,000 for the first time since March. The FTSE 100 rose 1% to hit an all-time high.

Sure, why not?

Fears of a tit-for-tat escalation between the US and the world's second-largest economy have stalked investors' dreams for months.

The cost of commodities caught in the crossfire of early tariff talk - such as aluminium - had previously exploded higher as traders scrambled to figure out what the end of globalisation might mean for supply chains. Angela Merkel and other European leaders raced to Washington to secure exemptions from the conflict.

Yet here we are - barely a couple of months after the first shots in what now seems to have been only a phony war - and we have an armistice.

Will the peace prove phony, too? What are we meant to make of it?

The ups and downs of investing through a crisis

Personally, I think this trade tantrum has proven yet another illustration of why it seldom pays to invest with an eye on political news headlines.

Think about it. We entered 2018 hopeful that the first global synchronised expansion for years would turbo-charge economic growth everywhere - and that this would boost the bottom line of the companies we invest in.

Adding to this feel-good vibe were corporate tax cuts in the US that many believed would inject extra life into what's already a long economic expansion.

Shares raced out of the gate as December turned to January. Already expensive-looking US markets barely paused before hitting new highs by the end of the first month, and the rest of the world was carried along in their wake.

For the first time in this long bull market, conditions started to feel a tad... euphoric.

But the sudden emergence of tariff talk put a stop to that. US markets experienced their first sharp declines for over a year. The FTSE 100 dropped more than 10% in just ten weeks.

And then - coincidentally or not - the White House started to soften its rhetoric towards China. Combined with strong company earnings for the first quarter, sentiment shifted, and we'd begun to climb again, even before Mnuchin's latest proclamations.

One way to fewer sleepless nights

Of course, the smart thing to do was to ignore the whole spectacle.

Imagine a Foolish investor who checked their portfolio at the end of 2017 and then made a note not to look again until after the Royal Wedding. They would have probably shrugged to see their portfolio's valuation largely unchanged over the past five months.

So much for the scary volatility of stock market investing! They'd have missed the entire ride, and been much happier for it.

They could also have spent more time doing what really matters as an active investor - researching companies, reading their results and their plans, and trying to find those most likely to succeed over the next 5-10 years, rather than the next news cycle.

But then there was Brexit

The hard part to this appealing strategy of ignoring the noise is just occasionally the explosion you hear really does signify something important has blown up.

Brexit is a great example. Professional investors were mocked as out-of-touch on the night of the EU Referendum when it became clear that the British public had - against expectations - voted to leave the EU. Sterling reversed and began sinking towards record lows against the dollar.

Yet the winning margin was not vast. If 700,000 of the 17.4m who voted Leave had voted to Remain, someone like me would have been writing an article just like this saying it's best investors ignore political kerfuffle.

That was the lesson from the Eurozone crisis, wasn't it? Again and again, crucial votes turned out to be anti-climactic from the perspective of the markets.

Of course, you might still argue the same thing is true of Brexit. But I would say our Referendum was a rare exception that proved the rule that 'nothing much happens, most of the time'.

Stick to the fundamentals

Then again, perhaps we haven't seen the last of this trade dispute with China.

Maybe President Trump just wants to get his economic rivals on side for now before he makes a run at claiming the Nobel Peace prize for ending the standoff on the Korean peninsula.

Stranger things have happened. (Not much stranger, I admit.)

It's not that geopolitics never matters to investors, or that nothing ever changes. It's that it's all but impossible to anticipate, to gauge, and to profit from it.

There are already enough things to think about as a private investor looking to find the best companies at undervalued prices without adding in the near impossible.

It's better to leave the grand bluff and counter-bluffs to the politicians.

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