The New Democrats and their leader, Jagmeet Singh, are breathing a big sigh of relief after Monday’s byelection victory in Burnaby South, B.C. But they should think twice if they think they can stop waiting to exhale, because it’s only a small (albeit significant) hurdle that’s been cleared. Mr. Singh has a lot of ground to make up after nearly a year and a half of leading the NDP from outside of the House of Commons. He may not be a political-theatre neophyte, having held a seat in the Ontario legislature, but he hasn’t had the chance to prove he can hold his own on the national stage in the House. After raising his arms in victory in October 2017 as the winner of the leadership contest, Mr. Singh said he wasn’t concerned with the fact he didn’t have a seat in the House of Commons. "I'm comfortable right now with the fact that I don't have a seat," Mr. Singh told reporters in Ottawa the day after the vote. He invoked the beloved late leader Jack Layton, noting that he also was seat-less for more than a year when he took the party’s reins in 2003. He said he didn’t think it would be difficult to stay relevant despite not being in the House, but that he was open to running anywhere in the country. “I think it’s important to have an authentic connection to the riding, and there’s different places that I have an authentic connection,” he said, mentioning that he’d lived in Newfoundland and Labrador, Windsor, Ont., as well as the Toronto area. But, as we all know, Mr. Singh landed (some may even say parachuted) into British Columbia. And he’ll soon be able to finally square off against Prime Minister Justin Trudeau himself in the House of Commons, instead of outsourcing the job to parliamentary leader Guy Caron. Though Mr. Singh may have been comfortable with staying out of Ottawa for as long as he did, it’s unlikely he’ll be afforded much cushioning when he makes his House debut. As he’s proven at victory parties and Parliamentary Press Gallery dinners, Mr. Singh is light on his feet. But he won’t have much time to find them. MPs of the non-New Democrat persuasion have been known to engage in a popular heckle of “who?” when Mr. Singh’s name is raised in the House of Commons, and despite not being involved in the daily fray, he still managed to make headlines—many of which were early obituaries for his continued leadership prospects. He’s coming in the final throes of the parliamentary session, when tempers are high, narratives are entrenched, patience is short, and barbs are sharp. A looming general election and the siren call of summer means everyone on the Hill (yes, journalists, too) is out for blood. Rookie mistakes will be blown up and out of proportion and there isn’t a lot of time left for memories to fade. Welcome to Parliament Hill, Mr. Singh, and good luck. You’ll need it.