President Obama. That’s who.
And bear in mind the following from Jake Tapper:
During his presidential campaign, then-Senator Obama was quite critical of the Bush administration’s uses of signing statements telling the Boston Globe in 2007 that the “problem” with the Bush administration “is that it has attached signing statements to legislation in an effort to change the meaning of the legislation, to avoid enforcing certain provisions of the legislation that the President does not like, and to raise implausible or dubious constitutional objections to the legislation.”
Then-Sen. Obama said he would “not use signing statements to nullify or undermine congressional instructions as enacted into law.”
I have no doubt what President Obama is now doing with signing statements is entirely Constitutional. Of course, President Bush’s signing statements were entirely Constitutional as well, but people like Barack Obama chose to ignore that fact for partisan purposes, and chose to engage in an attack against the Administration that turned out to be hypocritical in the extreme.