Japan will be lowering its corporate tax rate. The result will be to make the United States' statutory tax rate (the tax rate on paper) the highest tax rate in the developed world (if you also exclude Japan's added value tax).
What you'll be hearing from Republicans:
“The United States is a world leader in countless ways. ‘World’s Highest Taxes’ is a title we should give up as soon as possible.” - Sen. John Barrasso (R-WY)
“This isn’t an April Fool’s Day joke; as of April 1, the United States of America will have reached the inauspicious position of having the highest corporate tax rate in the developed world. I want America to be number one in many things, but having the highest corporate tax rate is definitely not one of them.” -Sen. Orrin Hatch (R-UT)
What the reality is:
While the US has a high statutory tax rate, it also has one of the lowest effective tax rates for corporations. In fact, in 2011, what corporations actually paid fell to a 40 year low of 12.1%. This means corporations are actually paying less in taxes in the US as they achieve post-recession, record profits.