(Adds U.S. market open; changes dateline; previous LONDON)
* Dollar enters sixth session of selling
* EM stocks extend gains on dollar fall
* Manafort conviction and Cohen guilty plea add uncertainty
* Graphic: Earnings growth in U.S. and Europe: reut.rs/2LkECRE
* Graphic: World FX rates in 2018 tmsnrt.rs/2egbfVh
By Herbert Lash
NEW YORK, Aug 22 (Reuters) - Benchmark U.S. government debt yields slid to six-week lows on a flight to safety bid and the dollar weakened further on Wednesday as investors assess how a conviction and a guilty plea of two former advisers impact U.S. President Donald Trump.
A gauge of global equities rose, lifted by higher energy prices and strong earnings from retailers in a session that marked the longest U.S. bull market. It came a day after the S&P 500 stock index set an all-time high.
U.S. Treasuries yields also fell as contentious trade talks between U.S. and Chinese officials were set to resume on Wednesday and as investors looked to minutes from the Federal Reserve's August meeting due later in the session.
"Beyond the political uncertainty associated with what's going on in Washington, there are broader macroeconomic concerns resulting from on-again, off-again trade tensions and of course where the Fed stands on this," said Ian Lyngen, head of U.S. rates strategy at BMO Capital Markets in New York.
Trump's former lawyer, Michael Cohen, pleaded guilty to charges of tax evasion, bank fraud and campaign finance violations on Tuesday as the president's former campaign chairman, Paul Manafort, was convicted on eight charges.
Cohen would not accept a presidential pardon, his attorney said, and he wanted no part in what Trump's former adviser saw as the president's abuse of his clemency power.
Cohen also questioned Trump's loyalty to the United States and saw him as unfit to hold office, his attorney, Lanny Davis, said in a round of television interviews.
Equity investors appeared less concerned about Trump as Wall Street marked what is widely considered a bull market that started in the midst of the global financial crisis a decade ago that wiped out more than half of the U.S. stock market's value.
The benchmark S&P index has more than quadrupled since the lows of March 2009. (Full Story)
Markets are likely to be whipped around in coming months by the outlook for mid-term U.S. elections in November, the probe of Russian meddling in the 2016 U.S. election and the Fed's monetary policy, said Phil Orlando, chief equity strategist at Federated Investors in New York.
With the next earnings season two months away, an information vacuum on corporate fundamentals could lead stocks to decline 5-8 percent, Orlando said.
"The potential for an air pocket here is pretty good," he said.
MSCI's gauge of stocks across the globe gained 0.30 percent and its emerging market index rose 0.51 percent.
In Europe, the pan-regional FTSEurofirst 300 index closed up a preliminary 0.04 percent.
At midday, the Dow Jones Industrial Average fell 5.87 points, or 0.02 percent, to 25,816.42. The S&P 500 gained 3.94 points, or 0.14 percent, to 2,866.9 and the Nasdaq Composite added 32.15 points, or 0.41 percent, to 7,891.32.
The dollar index fell 0.12 percent, with the euro up 0.19 percent to $1.1591.
The Japanese yen weakened 0.24 percent versus the greenback at 110.57 per dollar.
Benchmark U.S. Treasury 10-year notes rose 5/32 in price to yield 2.8279 percent.
Oil hit a two-week high above $74 a barrel as an industry report showing a sharp drop in U.S. crude inventories and U.S. sanctions on OPEC producer Iran pointed to tighter supplies.
Brent crude, the international benchmark, rose $1.72 to $74.35 a barrel. U.S. crude gained $1.79 to $67.63.
Oil also found support from the weaker dollar, which makes oil less expensive for buyers using other currencies.
The prospect of a drop in oil exports from Iran, the third-largest producer in the Organization of the Petroleum Exporting Countries - in response to new U.S. sanctions - was also supporting the market.
Additional reporting by Helen Reid and Abhinav Ramnarayam; editing by Andrew Heavens and Dan Grebler