A trade deal with China could stop the dollar's rise, but it may not stay down if President Donald Trump then turns his focus to tariffs on European cars.

U.S. trade negotiators are in China this week, and stocks and risk assets have risen on optimism that a deal will be reached and that Trump will not impose new sanctions on the March 1 deadline, if talks are continuing. At the same time, the dollar has moved higher, after a series of more positive U.S. data, including Thursday's CPI.

"When you look around the world, that seems to be where the big economic risks are emanating from. The U.S. economy is slowing, but it's still growing above trend," said Marc Chandler, Bannockburn Global Forex chief market strategist. "The dollar has gone up every day, except for one, since the jobs data, and that's right after the Fed sounded so dovish."

The dollar index has risen 8.4 percent over the past year, boosted by concerns that trade wars and tariffs will harm the global economy. But recently, its rise has been fueled by the economic data, after January's robust jobs report reduced worries about a recession. Trump has said in the past that a strong dollar hurts the U.S. while other countries manipulate their currencies, but other administration officials have backed a stronger dollar.

Strategists say the initial reaction in the dollar, should the U.S. and China come up with a trade deal, would be a decline, as emerging market currencies jump and the euro gains, at least in the short term.

But the Commerce Department is soon expected to release the results of its study of the global automobile industry, through the prism of national security concerns, and many analysts believe it will recommend tariffs on European vehicles. The report is expected Feb. 17, and the administration would then have 90 days to act on it.

Mark McCormick, TD Securities head currency strategist, said the euro could head to the top of its recent range, to about $1.16 after a China deal. "If there are European tariffs, we're going to 1.10," he said. Euro/dollar was at 1.1264 Wednesday.

"The markets are trying to price different outcomes, and they're all overshooting because nobody has any conviction on what to do on any asset class," said McCormick, of the effect of trade wars. "It weakens global growth. It impacts U.S. multinationals' operations. It impacts local economies. It changes the trajectory of monetary policy. It becomes a very challenging environment to build scenarios around. Everybody is just kind of waiting for some solution, whether it's Brexit, Trump China trade issues, some of the broader discussions around trade."

The euro, in the meantime, has been responding to weakness in European data, concerns about Brexit and trade uncertainty. Trade experts have said the U.S. will likely reach a China deal before turning its sights on Europe and then Trump may well impose tariffs.

"Auto tariffs would hit the euro zone very sharply. That would be a negotiating tactic. I think the problem with this again is you might have a very adverse reaction in global financial markets since that kind of thing would undermine the sustainability of that kind of approach," said Ben Randol, G-10 foreign exchange strategist at Bank of America Merrill Lynch. "It just feeds the narrative of a generalized global trade uncertainty."

The euro would dive on new tariffs, and the dollar would strengthen.

"The U.S. dollar goes up on issues of trade uncertainty because the rest of the world is hurt more," said Randol.