Wisconsin liberals hope to take a key step this spring toward breaking a long conservative stranglehold on the state's Supreme Court, in an election that could also serve as a barometer of the political mood in a key presidential swing state.

If the liberal-backed candidate wins the April 2 state Supreme Court race, liberals would be in prime position to take over the court when the next seat comes up in 2020 — during a presidential primary when Democrats expect to benefit from strong turnout.

The bitterly partisan court, which conservatives have controlled since 2008, has upheld several polarizing Republican-backed laws, none more so than former GOP Gov. Scott Walker's law that essentially eliminated collective bargaining for public workers.

If liberals can win in April and again in 2020, they would have the majority until at least 2025.

"It is absolutely critical we win this race," liberal attorney Tim Burns, who lost a Wisconsin Supreme Court race in 2018, said of the April election. "It does set us up for next year to get a court that's likely to look very differently on issues of the day like voters' rights and gerrymandering."

The court could face big decisions on several partisan issues in the coming years, including on the next round of redistricting that follows the 2020 Census, lawsuits challenging the massive Foxconn Technology Group project backed by President Donald Trump, and attempts to undo laws that Republicans passed during a recent lame-duck session to weaken the incoming Democratic governor before he took office.