So Barack Obama can promise tax cuts by “the closure of corporate tax loopholes and tax havens.”
He’s right: he can.
He can close loopholes and tax havens (well, at least in theory he can) and thus raise the effective tax rates that corporations pay, thus leaving room to lower other taxes on other people. That he might be able to do.
But raising more money from one group and then less from another is not "tax cuts". That’s a redistribution of the tax burden.