While it seems that trade disputes between the US, Mexico, and Canada are de-escalating, the trade conflict with China is not. President Trump ramped up the trade war on Monday as $200 billion in Chinese imports took effect. This is the third round of US tariffs on Chinese imports, a significant escalation of the conflict between the world's two largest economies.

And caught in the middle of the crossfire are US retailers, who have spent a great deal of time on investor conference calls warning about imminent price hikes during the upcoming holiday season, which could send shock waves through the wallets of American consumers.

The chief executives from Walmart, Target, Gap Inc. and Best Buy, among others, have been some of the most vocal companies warning about "unavoidable" price hikes.

According to a letter from Robert Lighthizer, the US Trade Representative, tariffs on some $200 billion worth of Chinese imports took effect Monday. There are several hundred items on the list, including electronics, kitchenware, tools, and food. The taxes are set around 10 percent but will jump to 25 percent at the beginning of 2019.

The resulting margin compression will force retailers to either eat the cost of the tariffs or pass it along to consumers, right before the critical holiday season: "The new tariffs are bad news for the retail sector, especially as the latest round seems to extend the tax to a vast array of consumer goods," GlobalData Retail Managing Director Neil Saunders said in comments emailed to Retail Dive.

"Many retailers will now be faced with a difficult choice of whether to pass the cost increases across to consumers or to take a hit on their margins. The exact response will vary from retailer to retailer but, both strategies are likely to be used."

In a late cycle economic environment, tariffs are especially dangerous for retailers because it could exacerbate the effects of other rising costs, "including more spending on technology, elevated logistics costs, higher gas prices, and rising labor expenses. In short, additional tariffs are the last thing the retail sector wants," according to Saunders.

The new duties are across a wide assortment of goods, from apparel to appliances, mainly covering consumer products. Retail Dive said some retailers are working with suppliers on how to respond to their impact, while others look to shift their manufacturing bases.

Reshifting supply chains takes time and are very costly. Some small and medium-sized companies could face financial hardship due to the disruptions.

"Of course, it’s also related to the ability of our vendors to observe the tariffs, and of course we are having negotiations, or over time, usually not in the short term but over time, to diversify the supply base," Best Buy CEO Hubert Joly told investors last month, according to a conference call transcript. "So, it’s a complex undertaking."

Before the holidays, price hikes on low-margin consumer goods are inevitable. "As we said many times, as a guest-focused retailer, we're concerned about tariffs because they would increase prices on everyday products for American families," Target CEO Brian Cornell said last month, according to a conference call transcript.

"In addition, a prolonged deterioration in global trade relationships could damage economic growth and vitality in the United States. Given these risks, we have been expressing our concerns to our leaders in Washington, both on our own and along with other retailers and trade association partners," Cornell said.

Last week, Walmart sent a letter to the Office of the United States Trade Representative, warning that the trade war impact will soon lead to price hikes.

The result of $200 billion in new tariffs "will be to raise prices on consumers and tax American business and manufacturers," Walmart said in the letter. "As the largest retailer in the United States and a major buyer of U.S. manufactured goods, we are very concerned about the impacts these tariffs would have on our business, our customers, our suppliers and the U.S. economy as a whole."

In an interview last Thursday, Gap Inc. CEO Art Peck told Bloomberg's Emily Chang, the company is watching the trade situation closely, but implications are not as great for Gap because apparel is not on the list. The company has spent years diversifying its manufacturing plants across many countries. But Peck said a jump in prices would eventually hit the consumer's wallet as a result of President Trump's trade wars.

So from now until the rest of the year, retailers will factor in about 10% tariffs. But when 2019 comes around, the tariffs are set to rise to 25%. "Should an agreement between China and the U.S. not be found before the New Year, retailers could well start 2019 on a gloomy note," Saunders warned.

An all-out trade war between the US and China is emerging as the most plausible scenario for 2019 and beyond, a risk that could severely impact US retailers and the American consumer.