Washington (CNN) Democrats picked off another Republican-held state legislative seat in a special election Tuesday -- this time a suburban, Sarasota-area district in Florida.

Margaret Good's win over James Buchanan -- the Republican whose father is US Rep. Vern Buchanan -- is another worrying sign for national Republicans headed into next fall's midterm elections.

Good won by 7 percentage points in a district that President Donald Trump carried by 5 points in the 2016 election.

That swing in Democrats' direction made the Florida contest the 36th GOP-held state legislative seat to change parties since Trump took office. And in a district where Republicans held a voter registration advantage of nearly 13,000, the Democratic Party sees it as evidence it can win in Republican strongholds.

It's far short of the nearly 1,000 seats Republicans won during former President Barack Obama's tenure, but Democrats see the wins as signs of an energized base that could deliver control of the House, and potentially the Senate, to the party in this year's midterm elections.

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