An earlier version of this post incorrectly quoted Karl Rove as saying “people between the ages of 16 and 13.” This post has been updated.

On Friday the president declared he could effectively amend the law he has sworn to uphold by refusing to enforce those he doesn’t care for. The ball is now in Congress’s court to pass its own legislation and/or respond to the president’s bald-faced power grab.

On “Fox News Sunday,” Karl Rove explained what is at stake:

Well, first of all, I appreciate President Obama continuing the Bush policy era policies of prioritizing investigations and removals of criminals, criminal aliens. But look, we examined these questions significantly during the Bush years and concluded we had no statutory authority to offer in essence a blanket exemption from deportation without a change in the law. And this is what troubles me.

This makes — if the president felt so keenly about this, he’s had three years to get something done on it. And I don’t think he has statutory authority to do this in a blanket way. . . .

There is no ability in the law to basically say we are going to create whole groups of people, not individuals, but groups of people — in this case, people between the ages of 16 and 30 as being exempt from the provisions of the law. And so I think he’s on very shaky grounds.

As a preliminary matter, it would be helpful for that legal analysis to be aired and to demand that the Obama administration provide its own analysis. Did the Justice Department render an opinion telling President Obama that after disclaiming such authority he actually had authority to alter immigration law in this fashion?

Congress must promptly move forward or risk ratifying by silence Obama’s dangerous precedent in sidestepping the legislative branch. First, Sen. Marco Rubio (R-Fla.) could and should come forward with his own bill, which can be debated and voted upon. Second, the House and Senate should hold hearings on the president’s gambit, solicit expert opinion and, if warranted, vote to admonish the president for his hubris.

As for Mitt Romney, he should be putting some weight behind both of these actions. It is wise for him to be on the side of the rule of law and in favor of an enforceable, reasonable solution to the issue of minors brought to the country illegally.

The president frankly has gotten off easy. On “Face the Nation,” Romney scolded Obama for enacting a “stopgap” measure. In fact, it’s an illegal power grab, evidence that this president is incapable of working with Congress and must resort to extra-constitutional means to govern.

Romney advertises himself as someone who was able to work with a Democratic legislature to get things done. He would be wise to highlight the contrast between his legal, collaborative style with Obama’s imperious hostility to the legislative branch.