There is a very good reason that most presidents reach across the aisle to build relationships and decide against constantly lying about things both big and small. Enacting an agenda as the head of the executive branch usually means cajoling the opposition into action, which itself often means having to demonstrate that the opposition’s base won’t revolt against the president’s idea.

This is not the path President Trump chose. He chose to continue the pattern he demonstrated during the campaign: Lying or misleading about things big and small and focusing his attention and energy almost exclusively on his core base of support.

His thinking seems to be: Hey, it worked for me in 2016. But it’s worth wondering what his presidency would have looked like had he approached the job with a more traditional, inclusive approach. There would still have been many skeptical Democrats, certainly, but it’s more than possible that much more of the Democratic base and many more independents would be willing to give him the benefit of the doubt. Trump says there’s an emergency on the border? Well, many more voters might have thought, we can trust him to both be honest about that crisis and to be putting the country’s needs first.

So we end up with poll numbers like this one, from Fox News.

Only about 20 percent of Americans think that there’s an emergency on the border — including only 4-in-10 Republicans. Trump has insisted that it’s an emergency, even toying with the idea of declaring a national emergency to get a wall built. But Americans aren’t convinced.

It’s not clear, in fact, that Trump’s convinced Americans of much. A poll from the Associated Press and NORC asked respondents what effect they thought the construction of a wall might have, specifically focusing on issues that Trump has touted as problems that the wall would solve. The result? Most Americans — often including Republicans — don’t seem to be buying Trump’s rhetoric.

For example, the pollsters asked if a wall would make the country more safe, a central tenet of Trump’s pitch. Only about a third of the country said it would, including about 3-in-10 independents.

Note that three-quarters of Republicans agreed with Trump’s position. That’s a bit more than the two-thirds who accept Trump’s argument that the wall would sharply affect the number of immigrants entering the country. Only about 3-in-10 Americans overall believe the wall will have that effect — a remarkably low percentage given how central this claim has been to Trump’s rhetoric.

Compare the Republican responses above to another question raised in the poll: Would the wall improve the health of migrants? In his speech last Saturday, Trump focused on the risk posed to migrants, including sexual assaults, implying that the wall would address that issue. Fewer than half of Republicans think that’s the case, and less than a quarter of all respondents.

Perhaps most remarkable is the response when the AP-NORC asked about the flow of drugs across the border. Trump has argued that a wall could halve the drug problem and crime rate nationally — but even most Republicans don’t buy it.

For good reason, of course. Most of the drugs seized at the border are seized at existing ports of entry, with smugglers hiding them in vehicles or on smugglers' bodies. Trump’s argument is incorrect, and Americans aren’t accepting it.

How unsuccessful has Trump’s sales pitch been on the wall? He’s twice given national addresses, one from the Oval Office, meant to convince Americans of the need for a wall.

After each, his approval rating has gotten worse.

Trump’s response has been brute force, trying to win the fight by getting his opponents to buckle. That hasn’t worked.

Bringing us back to our original point. Trump’s push for a wall appears to be seen as a response not to a crisis on the border but as an attempt to yet again deliver on a campaign promise for his base. Had this fight not been spurred by complaints on conservative media, had Trump approached his entire presidency differently, had he demonstrated a reliability on his rhetoric and a willingness to reach across the aisle, who knows what the current fight might look like.

Almost certainly not like this.