* New York, other states take on Trump over energy efficiency
* Investors fret over govt ability to deliver on reforms
* Most S&P sectors lower, some defensive sectors up
* Earnings season, Trump-Xi meeting also in focus
* Indexes down: Dow 0.14 pct, S&P 0.26 pct, Nasdaq 0.26 pct (Updates prices, adds commentary, changes byline)
By Sinead Carew
April 3 (Reuters) - Wall Street fell on Monday as investor worries intensified about the Trump administration's struggles to deliver on its pro-business policies a few weeks before the first-quarter earnings season.
Stocks had risen to record highs on Trump's promises to cut tax, ease regulations and spend heavily on infrastructure.
The major indexes pared losses in the afternoon. They had tumbled earlier after some U.S. states accused President Donald Trump's administration of illegally suspending energy efficiency standards.
The challenge came barely two weeks after Republican's had to pull healthcare reform bill due to a lack of support. Also on Monday, Democrats amassed enough support to block a confirmation vote for Trump's Supreme Court nominee.
"If there's not one big reason (for the market decline), there's many little reasons. Right now I think it's a little reason day," said Brad McMillan, Chief Investment Officer for Commonwealth Financial in Waltham, Mass. "I'd expect it to trade in a fairly narrow range until something knocks it out of that range. Right now there's not a lot of meaningful news."
While investors still hope Trump can deliver on some of his agenda, they "are getting nervous and starting to discount some of the benefits they expected to see."
"The opera is not over yet but maybe you can see the end of it from here," said McMillan.
Weeks ahead of the start of first quarter earnings season investors would need a clear reason to buy, he added. The S&P 500 is trading at about 18 times earnings estimates for the next 12 months, above its long-term average of 15.
Adding to nerves was news of a explosion in a St Petersburg train tunnel that killed ten people on Monday in what Russian authorities called a probable terrorist attack.
Trump held out the possibility on Sunday of using trade as a lever to secure China's cooperation against North Korea, in comments that appeared designed to pressure Chinese President Xi Jinping ahead of his first meeting with Trump later this week.
The Dow Jones Industrial Average fell 28.53 points, or 0.14 percent, to 20,634.69, the S&P 500 lost 6.15 points, or 0.26 percent, to 2,356.57 and the Nasdaq Composite dropped 15.47 points, or 0.26 percent, to 5,896.27.
The CBOE Volatility index, known as Wall Street's 'fear gauge' was up 2.5 percent at 12.73 points, on track for its third straight session of gains.
Eight out of 11 major S&P 500 sectors were lower, led by the materials index's 0.8-percent drop. Two of three positive indexes were telecommunications and real estate - defensive sectors whose predictable but slow growth are often popular in times of uncertainty.
Tesla shares gained as much as 6.9 percent to a record high after the electric car maker reported record first-quarter vehicle deliveries.
But, other automakers fell after reporting March sales that came in below market expectations. GM dropped 3.7 percent, Fiat Chrysler sank 4.5 percent, while Ford was off 2.4 percent.
NYSE declining issues outnumbered advancers 1.43-to-1; on Nasdaq, a 2.18-to-1 ratio favored decliners.
The S&P 500 posted 17 new 52-week highs and 6 new lows; the Nasdaq Composite recorded 77 new highs and 26 new lows. (Additional reporting by Yashaswini Swamynathan and Sweta Singh in Bengaluru, Rodrigo Campos in New York; Editing by Savio D'Souza and Nick Zieminski)