In 2009, President Obama proposed that US emissions in 2020 should be 14% below 2005's baseline, and that year the House of Representatives passed legislation that mandated a 17% reduction. (The Senate never passed the bill.)
So how is the US doing? Thanks largely to the surge in use of natural gas instead of coal, it's actually on-track to meet that target -- to meet it 3 years early, in fact:
And per capita emissions are, as of April of this year, even better: 13.2% below December 2005.
But Obama also proposed a reduction of 80% by 2050, which, despite the chart, is much more difficult (if not impossible, without new technologies.)
Note: These are emissions from fossil fuel use; they don't include those from land changes. They also don't include emissions embedded in the products purchased by Americans that are manufactured in other countries; by one estimate, 9% of China's emissions are from goods shipped to the US, and 6% from goods shipped to Europe. (HT: The Climate Fix). In 2010 that would add 749 Mt CO2 to US emissions (13%), and 11% to Europe's emissions.