CANONSBURG, Pa. — The final day of campaigning Monday before votes are cast in western Pennsylvania’s closely watched congressional election drew a visit by Donald Trump Jr. and lots of door-knocking all over the southwestern district where polls show a close race.

President Trump tweeted about “steel and business” in a final push to sway voters while Donald Trump Jr., visiting a candy-making business, touted Republican Rick Saccone as someone who will be “helping fight with my father” for jobs to come back from overseas.

Saccone, a 60-year-old state lawmaker, has struggled with an electorate that favored Trump by nearly 20 percentage points just 16 months ago. He’s up against 33-year-old Conor Lamb, who pitches himself as an independent-minded Democrat.

Trump Jr., eating ice cream with Saccone at Sarris Candies in front of dozens of cameras, said Trump supporters “gotta stay in the game, they gotta stay motivated.”

“Our guys just can’t take winning for granted,” Trump Jr. said. “They have to get out there, they have to continue this fight, now, for the rest of ’18, in ’20 and in eight years we can make a big difference. They just can’t be lazy. They’ve gotta get out and vote, and if they get out and vote, we win easily.”

The outcome Tuesday of 2018’s first congressional elections is a barometer ahead of November’s midterm elections.

Democrats must flip 24 Republican-held seats to claim a House majority. An upset would embolden them as they look to win in places where the party has lost ground in recent decades.