The Trump administration has been exhaustingly eventful, but almost none of the events have involved Congress.

The beginning of Donald Trump’s presidency has been an extension of the last six years of the Obama administration, when Capitol Hill was largely a sideshow to the main event in the executive branch in general and the Oval Office in particular. Barack Obama and Donald Trump have almost nothing in common, except their modes of governance.

Obama was coolly cerebral and deliberative to a fault, whereas Trump is blustery and impulsive. Yet Obama and Trump are both, in their own ways, attention-hungry celebrities. Obama never demonstrated the patience or aptitude for real persuasion, whether LBJ-style arm-twisting or Reagan-style move-the-needle public argument. Neither has Trump. Institutionally, Obama was content to be a loner, and so is Trump.

Until further notice, this is the American model — government by and of the president. We live in the age of unilateral rule.

It may be that Congress eventually passes Obamacare repeal-and-replace and tax reform, and makes its mark. Neither initiative is looking robustly healthy at the moment, though. And the action is all with Trump, what he does, says and tweets.

To his credit, Trump hasn’t pushed the constitutional envelope the way Obama did with his Clean Power Plan and his executive amnesty (both blocked in the courts). What Trump has done unilaterally has been firmly within bounds and largely defensive in nature. He has either reversed Obama actions or used executive orders as symbolic measures.

Still, the yin and yang from Obama to Trump means that American government has become a badminton match between rival presidents with dueling executive actions. As a result, our laws are largely contested in the realm of executive decisions, agency rule-making and the courts. Arguably, in striking down Trump’s travel ban on highly dubious grounds, the 4th Circuit has done more legislating this year than the United States Congress.

If Trump’s unilateral rule is an extension of what has come before, it also is an intensification.

First, there’s the timing. Ordinarily, a president loses Congress or otherwise stalls several years into his tenure, and looks to foreign affairs and executive orders for victories. Trump is already dependent on presidential unilateralism, even though his party controls both houses of Congress.

It’s not that Trump is deliberately cutting Congress out; he is desperate for it to get things done. He just doesn’t have the interest or knowledge to push legislation along.

Meanwhile, Congress has been handing over authority to the administrative state for decades, and lately has gotten out of the habit of passing almost anything except last-minute omnibus spending bills. The Senate, in particular, is debilitated by a near-automatic 60-vote threshold.

Second, there is the continued centralization of power in the White House. This has long been the trend, but President Trump has taken it to another level; he operates on a hub-and-spoke system with a small group of loyalists and family members jostling for influence around him.

The day Trump nearly initiated the process of pulling out of NAFTA captures the method perfectly — no serious deliberation, just the president’s state of mind, based in large part on whom he had spoken to last. This is highly personalized (and idiosyncratic) rule.

In the mid-1980s, the late political scientist Theodore Lowi wrote a book called “The Personal President.” It warned of the effects of a “plebiscitary” presidency unhinged from Congress and political parties. He was on to something, although Bill Clinton and George W. Bush subsequently governed fairly traditionally. It is with Obama and Trump that we have moved into a different gear.

No matter what the written rules are, any system of government is susceptible to change through habits and precedent. We may be witnessing the creation of a new norm, one that hollows out the branch of government charged with writing the nation’s laws.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.