Image copyright Getty Images Image caption The 2019 State of the Union has been postponed due to the government shutdown

There will be no fanfare tonight. There will be no pomp. And ceremony, forget it.

Tuesday's scheduled State of the Union address by the president has been postponed for at least a week because of the government shutdown, and that painful 35-day closure came about because of Donald Trump's insistence that he needed $5.7bn (£4.3bn) dollars for his border wall.

It is quite a good metaphor, really - a union divided by a wall.

Image copyright Getty Images Image caption Pro-wall protesters rally at the US southern border on 12 January 2019

Democrats in Congress oppose it - even though they have supported construction in the past along vulnerable bits of the border; Republicans do their best to sound enthusiastic about the president's signature campaign pledge, even though many are decidedly tepid.

Its construction has moved way beyond the relatively straightforward issue of border security and illegal immigration. It is raw politics dressed up in an occasionally see-through cloak of principle.

More on the US government shutdown

Is America a country that will be defined by the Statue of Liberty and the poem etched on it, "give me your poor, your huddled masses yearning to breathe free", ask high-minded Democrats.

Or will America be a country defined by a giant wall designed to keep those huddled masses from Central America out. That's the principle. The raw politics is that if Democrats can deny the president funding for his wall, then he will have failed to make good on his central election pledge that drove so many people to vote for this insurgent candidate in 2016.

So it was telling when Mr Trump caved in last Friday, he sought to redefine what his wall was - in a way totally different from how he'd originally outlined it - a concrete barrier across the southern desert.

Image copyright Getty Images Image caption "Read my lips, no new taxes," promised former president George HW Bush

Before this spectacular climb-down, he's reported to have said to an aide this mustn't be a "read my lips, no new taxes" moment.

What terrifies this president is the fate that befell the 41st president, George HW Bush. In the election of 1988, Bush senior had one simple pledge in his battle against the Democrat Michael Dukakis.

"My opponent won't rule out raising taxes. But I will," he told delegates at that year's Republican National Convention in New Orleans.

"And the Congress will push me to raise taxes and I'll say no. And they'll push, and I'll say no, and they'll push again, and I'll say, to them: 'Read my lips: no new taxes.'"

Image copyright Getty Images Image caption State funds kept the Statue of Liberty open during the shutdown.

But when the US economy went south and new taxes were introduced - it was a soundbite that would be endlessly played back to him, with a knowing sneer.

In the 1992 election, President Bush had the greatest foreign policy story to tell the American people - the end of the Cold War.

But it counted for nothing; it was his broken promise on taxes that people remembered. And as a new generation of Democrats line up to take on Donald Trump, again there are echoes of 1992, when George HW Bush found himself up against a young whippersnapper governor from Arkansas.

Image copyright Getty Images Image caption President Bush only served one term after losing the 1992 election to President Clinton

It seemed like a battle between the past and the future, as Bill Clinton ran rings around the president.

After Mr Trump agreed to reopen the government last Friday, without a single dollar pledged for his border wall, ambitious Democrats began licking lips.

Since Democratic House Speaker Nancy Pelosi has again extended an invite to Mr Trump to deliver his speech on 5 February, the stage is set for Mr Trump to continue pushing stubborn lawmakers or perhaps resort to other means.

And if House Democrats stand firm in their refusal to provide border wall funds, Mr Trump will be forced to either drop his signature campaign pledge - the one that led to so many thunderous chants at rallies - or perhaps issue a national emergency to bypass Congress.

After Mr Trump's retreat last Friday, one of the most influential voices on the right in America tweeted: "Good news for George Herbert Walker Bush. As of today, he is no longer the biggest wimp ever to serve as President of the United States."

Ouch. If he can't get that wall built, he's got serious problems.

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