A document with the Texas Republican Party’s strategy for the 2020 election was emailed to Democrats, showing a plan over the next 12 months to push back on the narrative that the GOP lacks diversity and counteract Donald Trump's potential negative impact on the race.

The document, which apparently began appearing in the inboxes of Democrats this week, lays out concerns about the "polarising nature" of Mr Trump's presidency, as well as ways to counteract the "narrative driven by Democrats" that the GOP lacks diversity in a state where a quickly growing Hispanic population has sowed considerable concern that the reliably red state could soon be competitive.

“Starting after the Primary, the RPT will generate microsites for negative hits against the Democrat candidates in our twelve target race—we expect each microsite to be roughly $500,” the document, which was obtained by the Dallas Morning News, reads.

The websites, according to the document, will mimic the names of Democratic candidates, and will reroute to pages featuring attack ads on those same individuals.

“We will then begin rolling out these websites, prioritising the races that were within 4 per cent in the 2018 election,” it reads.

The Morning News reports that Democrats see 2020 as an opportunity to build on gains they saw last year, when they took 12 seats from Republicans to narrow the partisan divide in the state House to 83-67.

Democrats, remarking on the apparently accidental leak, mocked the Texas Republican Party for the mishap.

“Republicans have already fumbled the ball and we aren’t even in 2020 yet,“ Manny Garcia, the executive director of the Texas Democratic Party, said in a statement.

He continued: “They know they’re in deep trouble ‘given the polarising nature of the President’ and expect ‘Republicans will refuse to turn out during the General Election because they don’t want to vote for him.’”

Democrats have their work cut out for them if they want Texas to be competitive. The state hasn’t voted for a Democratic presidential candidate since Jimmy Carter in 1976, and hasn’t had an elected Democrat in the Senate since 1993.

The stranglehold Republicans have on the state may be loosening, however, as evidenced by those 12 seats Democrats won in 2018 and the surprisingly close Senate run of former congressman Beto O’Rourke. Mr O’Rourke came within three percentage points of beating senator Ted Cruz in that race.