New York (CNN Business) 2019 was a heck of a year for US stocks, but can the market keep soaring in 2020?

Stocks face several obstacles to growth in the new year: The Federal Reserve has stopped cutting interest rates . The economic jolt from tax cuts has run out. Despite some progress, the United States still doesn't have a trade deal with China.

So stocks are entering 2020 with a bit less of a tailwind than they had in 2019. Investors still have plenty to be optimistic about, though.

The labor market is healthy and consumer spending remains strong, which bodes well for economic growth. The Federal Reserve Bank of St. Louis expects the US economy to grow less than 2% next year, but it noted that resolved trade tensions and a pickup in global growth could boost the pace of the economic expansion.

The United States and China gave the go-ahead to a preliminary "phase one" trade deal in mid-December. President Donald Trump said in a tweet Tuesday that the preliminary agreement will be signed on January 15. On the other hand, the countries still have much to negotiate and tensions with other American trade partners, including France and Germany, as well as Brazil and Argentina , will carry over into the new year.

Investors expect US stocks will keep climbing higher in the new year. But even the most bullish analysts predict a weaker rally than what 2019 offered.

S&P 500 SPX LPL Financial Chief Investment Strategist John Lynch forecasts the, which was at 3,214 as of Tuesday morning, will rise to between 3,250 and 3,300 points a year from now — a gain of between 0.9% and 2.5%. Citi calls for an increase of just under 5% to 3,375 points. US Bank Wealth Management's chief equity strategist Terry Sandven expects the index will end 2020 at 3,325 points, which would be a 3% gain.

That would pale compared to the whopping 29% gain the S&P saw in 2019.

Dow INDU S&P 500 INX Nasdaq Composite COMP Theandindexes are all ending 2019 near all-time highs and have rallied more than 20% each.

"In 2019, expanding valuations drove gains for stocks; in 2020, we expect earnings to do the heavy lifting," Lynch said.

Company earnings should be helped by clarity of the US-China trade front. Businesses held back on investments during the uncertainty of 2019. But business spending and productivity should rebound in the new year. America's ailing manufacturing sector , which has been hit hard by the trade war, could also recover.

New year, new risks

The new year doesn't come without its own set of risks.

Politics will be front and center, and the November 2020 presidential election could throw a wrench into the stock market rally. Much of the market's reaction will depend on who will emerge as the Democratic nominee to challenge President Donald Trump. The candidate's fiscal and economic policy plans will be closely scrutinized by investors.

Meanwhile, the high equity valuations in the United States could lead investors to look for better opportunities elsewhere. That could create a headwind for US equities.

Factors that could end the market's decade-long bull run which appear less imminent but are nonetheless risks investors should keep an eye on: rising interest rates, higher oil prices, or a recession to bring about the end of the longest economic expansion in history.

Even so, "our money will still stay in stocks this decade as bond yields and savings accounts interest rates are being held down by Federal Reserve policy," said Chris Rupkey, chief financial economist at MUFG.