Oil slides again, Apple's answer to voicemail and Tesla's support of fuel standards

The summer market doldrums have hit Wall Street with a mixed market to start the week. Weak economic data and another slide in crude prices has the S&P 500 (^GSPC) and Dow Jones Industrial Average (^DJI) in the red to start August but not by a frightening margin.

Here are some of the other stories Yahoo Finance is keeping an eye on today.
Big week for politics
It's a big week for the large field of Republican presidential hopefuls. Tonight there's a forum in New Hampshire with 14 candidates and then Thursday we'll get our first look at Donald Trump's debate skills when he and nine others take the stage in Cleveland. More than one news outlet is wondering whether Trump can sustain his lead once the Koch Brothers decide just who to back in the biggest of ways this cycle.

Tesla and fuel standards
While the auto industry is looking for ways to soften fuel-economy regulation. Tesla (TSLA) is presenting a public case to make the rules even more stringent. The electric car maker wants the 2025 fuel economy targets for U.S. auto manufacturers to remain at 54.5 miles per gallon.

Apple's Siri and the end of voicemail?
Apple (AAPL) is reportedly testing a service that would allow Siri to transcribe voicemail messages. Apple's i-Cloud service would then send users a text message of the voicemail. This new feature is expected to launch in 2016.