America's children celebrated Halloween last night, but its adults look set to unleash their own demons at the polls in tomorrow's midterm elections, effectively dooming the Obama agenda and ushering in a period of protracted political chaos and economic misery. The Republicans, buoyed by the Tea Party - a conservative populist movement funded by billionaires to channel the anger and anxiety of a struggling white middle class into blistering if incoherent rage - are on track to regain control of the House of Representatives and achieve effective veto power in the Senate.
And rather than using those gains to legislate, the Republicans have made clear that their priority is sabotaging Barack Obama's presidency. "The single most important thing we want to achieve," the Republican lead senator Mitch McConnell explained last week, "is for President Obama to be a one-term president."
America's economy remains mired in its deepest crisis since the 1930s, with no sign that it will create jobs for the 15 million unemployed in the foreseeable future; poverty is surging and infrastructure is crumbling as the threat of deflation looms ever closer; and an annual budget deficit of $1.5 trillion continues to swell the dizzying $13.5 trillion national debt. And what does the GOP plan to do with its electoral gains on Tuesday? Simply stop Mr Obama from passing legislation, and tie him up, as it tried to do with Bill Clinton, in an endless series of pointless congressional investigations.
Sober-minded economists warn that the economy is unable to generate sufficient domestic demand to create new jobs and spur an upward cycle of growth, meaning that government spending remains essential. But "stimulus" has become a dirty word in a political culture where banks and corporations are able to spend unlimited funds, in secret, on political advertising to convince voters that all state intervention in the economy is somehow redolent of communism.
Mr Obama and his political team appear to have been labouring under the comforting illusion that even if Republicans win big, they will have to either moderate their stance or face a repeat of the experience of the Clinton presidency. A surge by conservative Republicans to take control of the House in 1994 saw them overreach.
The Obama team has enjoyed watching the Republican establishment's candidates eclipsed by insurgent Tea Partiers in many nomination battles. Some Tea Party candidates on the ballot are so kooky as to make the Democrats' job easier, even though the demoralisation of their own base by Mr Obama's coddling of banks and corporations, and his continuation of Bush-era national security policies, will result in lower turnouts that will amplify the Republican vote this week.
But Democrats take heart from the likes of Christine O'Donnell, a Tea Party candidate who beat out the establishment nominee for the Republican nomination in a Maryland senate seat in which the Democrats were vulnerable. Her comments, such as "Where in the Constitution is the separation of church and state?" (Answer: in the First Amendment), have opened her to ridicule.
The Obama administration would love nothing better than to run for re-election against the Tea Party's clear presidential favourite, the former Alaska governor Sarah Palin. But the same moneyed interests that have nurtured the conservative insurgency are unlikely to oblige. They'll back Ms Palin only if she's deemed electable; if not, they'll allow Ms Palin's movement to wreck the Obama presidency, and then channel their resources behind a Republican nominee capable of winning uncommitted voters (and ensuring Ms Palin isn't able to wreck the plan).
The GOP's major donors came up with George W Bush as an apparently moderate candidate in the late 1990s, after unleashing the more demagogic likes of the former House speaker New Gingrich to bloody the Clinton administration. Nobody ought to be surprised if the incoming Republican majority in the House finds some outlandish reason to seek Mr Obama's impeachment.
So what impact would hobbling Mr Obama domestically have on his policies in the Middle East? The political textbook suggests that a domestic logjam might prompt him to seek achievements abroad, by pressing harder for an Israeli-Palestinian peace agreement or a diplomatic solution to the Iran nuclear stand-off. But the Republican strategy of waiting out the final two years of a one-term Obama presidency is also widely assumed to be shared by the Israeli prime minister Benjamin Netanyahu.
The Israeli leader managed to successfully resist US pressure when Mr Obama was at his political peak; saying no to the White House is only going to get easier because fierce opposition to any pressure on Israel is one of the of the few points of consensus between most of the Tea Party's angry base, the Republican establishment, and even most of the Democrats in Congress. Another is the idea that the administration needs to get more confrontational on Iran.
Indeed, if Mr Obama were a truly cynical politician (and there are no signs yet that he is) he might recognise that he'd find it easier achieving bipartisan cooperation through military confrontation with Iran than by seeking rapprochement with a regime that most of Washington is never going to trust.
Still, mindful of the dangers of dragging an overburdened empire into yet another potentially catastrophic war, Mr Obama remains likely to resist pressure to attack Iran. But just as his already limited ability to respond to the deep crisis in the US economy will be further limited after tomorrow, so has there been a decline over the past decade in Washington's ability to project influence to resolve complex problems in the Middle East. The harsh reality for Mr Obama is that the Middle East's key power players are no more inclined to do his bidding these days than are the Republicans who look set to take charge of the House of Representatives.
Tony Karon is a New York-based analyst who blogs at www.tonykaron.com