Republicans narrowly held onto a congressional seat in Kansas Tuesday, where State Treasurer Ron Estes won the special election in the state’s 4th District by a much thinner margin than expected.Democrat challenger James Thompson lost the mostly rural district by only about eight percentage points, or just over 9,000 votes, by the time the race was called late Tuesday night. By contrast, Republican Rep. Mike Pompeo, who left the seat to head the CIA, won the district by more than 30 points in the November election.But with an unpopular governor and President Trump’s approval ratings plummeting, Pompeo’s vacated seat started to look less and less secure. An internal poll last week reportedly found Estes leading by just a single percentage point.The narrow race was made all the more striking by the political firepower deployed — and not deployed — during the campaign. Democrats spent virtually no money on Thompson; the state Democratic Party originally declined to even give his campaign enough money for a mailer. But Estes had the support of a virtual campaign bus full of big-name Republicans, including Republican Texas Sen. Ted Cruz, who flew out to campaign with Estes, and both Vice President Mike Pence and President Trump, who recorded robo-calls urging people to vote for him.Still, the fact that the race was so close may be a warning sign for Republicans about the way Trump’s declining popularity could trickle down in the four upcoming congressional seat special elections and the looming 2018 midterms. The next special election will take place next week in a historically conservative Georgia district that Trump won by only one percentage point.