Day of reckoning approaches in high-stakes US midterm elections

The day of reckoning for US politics approaches as Americans prepare to go to the polls.

There are indications that a so-called “blue wave” may help Democrats seize control of at least one chamber of US congress.

However, two years after an election that proved pollsters and political commentators wrong, nothing is certain on the eve of the first nationwide elections of the Trump presidency.

All 435 seats in the US house of representatives are up for re-election. Another 35 US senate seats are in play, as well as almost 40 gubernatorial votes and the balance of power in virtually every state chamber.

While he is not on the ballot, Mr Trump has acknowledged that the 2018 mid-term elections represent a referendum on his presidency.

Perhaps more importantly, they would also win subpoena power to investigate the president’s many personal and professional mis-steps.

Tuesday’s elections will also test the strength of a Trump-era political realignment defined by evolving divisions among voters by race, gender and especially education.

Mr Trump’s Republican coalition is increasingly becoming older, whiter, more male and less likely to have a college degree. Democrats are relying more upon women, people of colour, young people and college graduates.

The political realignment, if there is one, could re-shape US politics for a generation.

A nationwide poll released on Sunday by NBC News and The Wall Street Journal details the depth of the demographic shifts.

Democrats led with likely African-American voters (84% to 8%), Latinos (57% to 29%), voters between the ages of 18-34 (57% to 34%), women (55% to 37%) and independents (35% to 23%).

Among white college-educated women, Democrats enjoy a 28-point advantage: 61% to 33%.

Democrats hope to elect a record number of women to congress. They are also poised to make history with a number of LGBT candidates and Muslims up and down the ballot.

Former president Barack Obama seized on the differences between the parties in a late scramble to motivate voters across America.

“One election won’t eliminate racism, sexism or homophobia,” Mr Obama said during an appearance in Florida. “It’s not going to happen in one election. But it’ll be a start.”

With a walking caravan of immigrants weeks away from reaching the border, Mr Trump dispatched more than 5,000 troops to the region. The president also said soldiers would use lethal force against migrants who throw rocks, before later reversing himself.

The charged atmosphere is expected to drive record turnout in some places, but on the eve of the election, it is far from certain which side will show up in the greatest numbers.

While Mr Trump is prepared to claim victory if his party retains senate control, at least one prominent ally fears that losing even one chamber of congress could be disastrous.

“If they take back the house, he essentially will become a lame-duck president, and he won’t win re-election,” said Amy Kremer, a Tea Party activist who leads the group, Women For Trump.

“They’ll do anything and everything they can to impeach him,” she said.

Powerful Democratic forces are already pushing for Mr Trump’s impeachment, even if Democratic leaders are not yet ready to go that far.