The theoretical rate is higher. But most corporations never approach that rate due to the numerous loopholes that American tax policy has which other countries don’t. You’ll notice that the people who call for a revision of the tax rate never mention these tax loopholes.
For someone who is not conservative, you laid out the answers very nicely! 
Rum, sodomy & the lash, if Congress’s private life is taken into account.
As far as I can tell, the Republican platform is as follows:
“Obama has made everything worse. We’re worse off in every way.”
Question: What would you do differently?
“Cut taxes!”
Question: How would that solve anything? Wouldn’t it increase the deficit?
“Gays in the military! Illegal immigrants!”
I disagree with those people. I demand a flat rate without loopholes, so that the owners of MSNBC can pay their taxes too.