Drawing together abolitionist and nativist anti-Catholic elements, it quickly became the dominant political force in the state and a powerful arm of the national Republican Party.

Following the Democratic victory in the 1856 elections and the Dred Scott case in 1857, the national American Party organization collapsed, and most Northern members joined the nascent Republicans.

In 1857, Banks ran as a Republican against incumbent Know-Nothing Governor Henry J. Gardner and won a decisive victory.

[citation needed] During a sixteen-year period from the onset of the American Civil War in 1861 until 1876, every statewide and federal elected office in Massachusetts was held by a Republican.

Banks briefly attempted to launch a presidential campaign in 1860 but failed to win support from the anti-slavery majority of the Massachusetts delegation.

Sumner stated that the Union government had the power to invoke martial law and emancipate the slaves.

This speech drew harsh criticism from the conservative Boston establishment but cheers from the party's abolitionists.

Radical Republicans, who were most aggressively supportive of the war, consolidated power and passed a wave of reforms.

During his governorship, Republicans repealed the constitutional restriction on immigrant voting Banks had supported[8] and passed the nation's first comprehensive integration laws.

As the national Democratic Party gained support in the urban North, Boston became competitive in statewide elections.

Liberal Republicans Charles Francis Adams Sr. and Benjamin Franklin Butler left the party and staged competitive bids for Governor on the Democratic ticket.

Lodge was a prominent advocate for restrictions on immigration and an antagonist of Democratic President Woodrow Wilson on matters of foreign policy.

In 1928, Catholic Al Smith became the first Democrat to win a majority of the vote in Massachusetts in a presidential election since the party's foundation a century prior.

With the emergence of Franklin Roosevelt's New Deal coalition and the growing power of the urban and Catholic vote, Massachusetts produced victories for Democratic presidential candidates in every election from 1928 to 1948.

Kennedy's victory over incumbent Henry Cabot Lodge Jr. in 1952 is symbolic of the long-term transition of power from Republican to Democratic in the commonwealth.

In 1966, Edward Brooke won a landslide victory to become the first popularly-elected black United States Senator.

In 1990, due to the unpopularity of then Governor Michael Dukakis at the end of his last term in office, Republicans led by gubernatorial candidate William Weld erased the Democratic super-majorities in the state legislature.

From 1990 until 2023, the governor's office had been consistently held by a number of Republicans, only interrupted by the governorship of Deval Patrick from 2007 to 2015.

In 2010, Republicans won a shock victory when Scott Brown defeated Democratic candidate Martha Coakley in a special election to succeed Senator Ted Kennedy.

However, Brown lost his bid for a full six-year term to Democratic challenger Elizabeth Warren in 2012.

[13] The leadership's embrace of Trump's positions has led to infighting among moderate and pro-Trump Republicans in the post-Trump era.