Frankenstein Government
On paper, North America was under solidly progressive governments, overturning the political status quo. However, in both Canada and the United States, the ruling governments were true Frankenstein coalitions. The Coldwell government only held power thanks to the right-wing Conservatives and...whatever Social Credit was (a strange big tent that included everyone from the far-right to the left). Similarly, the Siler administration was a hodgepodge of Christian conservatives, business types, old libertarians, and radical youth socialists. The reality of this was policy paralysis in both countries.
Vice President Johnson made his intentions clear: Siler should be a one-term President. Pulling strings in the Senate, the conclusion was clear: no legislation would take place until the Democrats took back the White House (with one major exception.) With a solidly Democratic Senate, legislation was dead in the water. For what it meant, this suited Siler quite well. Much of Siler's coalition demanded large expansions in the welfare state...which Siler, a fiscal conservative, largely did not want. Legislative gridlock was a remarkably good excuse for why he couldn't deliver. To the extent Siler had a domestic agenda, it was largely on the domestic front. Examples ranged from symbolic, an executive order adding "In God We Trust" to the Pledge of Allegiance, to substantive, such as ordering the government to recognize American victims of nuclear fallout (from the Three Years War). However, none truly transformed the field of American politics.
Siler had never really thought that much about race. Southern as he might have been, he came from an overwhelmingly white (Appalachian) district that had overwhelmingly sided with the Union during the Civil War. While generically in favor of Civil Rights and finding white supremacy offensive to his Christian principles, it was always a topic he essentially found fit to delegate to others with a larger stake in the whole issue. The policy wars of the Siler administration would ironically end up heavily focused on race. President McCarthy had started desegregation, President Kennedy had made the bulk of actual progress, and it was time for Siler to finish the rest. The last segregated public school in America folded in late 1965, a fact celebrated by the government. However, desegregation led to new, unique problems. Siler had inherited a serious problem of crime, urban decay, and "white flight", all driven by the collapse of industrial jobs (disproportionately those held by blacks) in the wake of the 1963 oil shock. One of the factors that led to a historic shift away from the Democratic Party was an unprecedented spike in crime, especially in economically hammered black neighborhoods. Moreover, the FBI under J. Edgar Hoover was so fervently anti-Siler (viewing him as a Communist), he received no help there.
As a Southern social conservative and with no federal police agency to help him, the Siler administration settled on an answer to crime: vigilantism. As part of the demobilization from the Kennedy period and the end of US participation in the Congo War, the United States had a lot of surplus weapons. Moreover, Siler was a balanced budget hawk. The result was a fire sale on American military weaponry. As part of an ongoing war with Hoover, the Department of Justice simply said that it would not be bringing cases under the National Firearms Act except to enhance sentencing for another crime (such as murder). Crime did actually go down during the Siler administration (albeit to nowhere close to 1950's levels), though it has been debated whether this was actually a result of Siler's gun policies (an alternative explanation points to a variety of federal racial equity undertaken by the federal government to lessen housing discrimination - as Johnson's gridlock strategy did have one major exception - civil rights law, which wasn't really possible to politically obstruct.) As a result, an endless bevy of lawsuits was brought against local governments, (mostly correctly) accusing them of unlawfully making policy moves on the basis of impermissible racial animus (such as housing, education, and policing policy). McCarthy's repeal of racial immigration laws had also come to fruition, as significant immigrant communities from Latin America began forming in American cities - and the Siler Administration alienated many middle-class Americans, especially Southern Californians, by restraining border security forces, officially apologizing for the Corpus Christi massacre, and generally taking a dovish approach to border control. As a result, Southern evangelicals loved Siler, but Californian evangelicals loathed him.
Effects on crime aside, the Administration's open embrace of vigilantism only supercharged ideological violence in the United States. Radical black liberationist and KKK gangs regularly shot each other up, often with fully automatic assault rifles. Amusingly, black radical groups used the AK-47 to symbol their fight, while white supremacist groups used the IKEA rifle to symbolize their cause, even though both sides tended to use surplus American weaponry. Moreover, middle-class Americans purchased weapons en masse. This had a tendency of radicalizing the police forces, which ended up disproportionately staffed by returning veterans from the Congo War, many who had essentially spent the last half-decade of their lives shooting at African guerillas. This skillset tended to map
extremely poorly onto inner-city policing, as police shootings of African-Americans skyrocketed. Interestingly enough, the end result of this was to solidify African-American support of Siler, as gun control was largely favored by conservative whites (who largely one-sidedly focused on the violence by black radicals) and the Democratic Party, and Siler resisted all calls for gun control, even threatening to pre-empt state gun control laws.
All of this naturally spilled over to Canada, even as the government was more functional. In fact, the CCF-Tory-Social Credit coalition actually managed to pass a massive expansion of the welfare state, including the creation of Canada's modern Old Age Security system and universal healthcare system, catching up to the United States (and arguably surpassing it with a more state-driven system). The Mounties were simply unable to stop the tidal wave of American weapons flowing into Canada, which significantly worsened a major crisis. Inspired by the Irish People's Republican Army assassinating the literal monarch of Canada, the Front de Liberation du Quebec (FLQ), was immediately formed afterwards, calling for a "Quebecoise People's War" to expel the "Anglo-Saxon imperialists." Establishing close links with the IPRA and black radical groups in America, the FLQ quickly surged in popularity, staging bank robberies, bombings, and other acts of "propaganda of the deed." Frankly put, not that many people died in FLQ attacks, which totaled at best a bad weekend in Chicago, causing the ruling government to simply...ignore the issue. This was seized upon by the Liberals, who quickly claimed they were the only party that could protect Canadian unity. Despite a very actually productive legislative agenda, the Liberals would once again take a commanding lead in the polls, which certainly made the ruling government worry about the 1968 elections (though it would also scare off any one party from collapsing the government and causing early elections).