Axios

President Trump has endorsed Darline Graham Nordone, the sister of late Sen. Lindsey Graham (R-S.C.), in next month's special election to replace Graham as the GOP candidate on the November ballot.

Why it matters: Nordone has not publicly confirmed plans to run, but Trump's endorsement will vault her ahead of other GOP candidates vying to replace her late brother.

President Trump is threatening to raise tariffs on Canada over wildfire smoke that drifted from the country into the U.S., triggering health warnings and disrupting outdoor activities.

Why it matters: Dealing with Canadian wildfire smoke is becoming a semi-regular occurrence in the Midwest and Northeast.

The Senate is set for another big House infusion next year.

Why it matters: The two chambers often clash over differing cultures and procedures. An influx of senators used to the faster, more confrontational politics of the House could create new headaches for Senate leaders.