With Sen. Ted Cruz’s departure Tuesday from the GOP presidential race, former New Mexico Gov. Gary Johnson is intensifying his push for the #NeverTrump crowd.

Mr. Johnson, a one-time Republican who’s running for the Libertarian Party nomination, urged disaffected Republicans and conservatives to support his presidential bid after real-estate mogul Donald Trump’s big win Tuesday in the Indiana primary.

Describing himself as the only viable small-government candidate left in the race, Mr. Johnson said Tuesday night that “the table for November’s election is set.”

“[The Cruz] departure from the race, along with the likely nomination of Hillary Clinton by the Democrats, makes it clear that neither of the two ‘major parties’ will offer voters in November a small government candidate,” Mr. Johnson said in a statement. “What they are offering voters are two of the most polarizing candidates in recent history.”

Mr. Johnson won just 1.2 million votes as the Libertarian Party’s 2012 presidential candidate, but the opposition to Mr. Trump among fiscal conservatives could swing alienated voters to the third-party nominee.

“With millions of Americans now feeling politically ‘homeless’, a two-term Governor who balanced budgets, cut taxes, cut regulations and truly reduced the size of government may offer the home they are seeking,” Mr. Johnson said.

He released a video Monday aimed at wooing undecided Republicans, saying, “Look, I can’t support Trump. You can’t either.”

The Libertarian Party presidential nominee will be selected at the national convention May 26-30 in Orlando, Florida. The theme is “Legalize Freedom.”