New Jersey became the latest state on Monday to boost its hourly minimum wage to $15 after Democratic Gov. Phil Murphy signed into law a measure phasing in the higher rate over five years. Murphy signed the bill alongside Lt. Gov. Sheila Oliver and Democratic legislative leaders at a raucous event in Elizabeth where advocates cheered, "Ready for 15," carried banners with their union affiliation and applauded loudly once the bill was signed.

"It is a great day to make some history for New Jersey's working families," Murphy said. "And that's just what we're going to do. We've talked long enough about putting New Jersey on a responsible path to $15 an hour minimum wage. Today we start our way on this path."

In this photo provided by the New Jersey Governor's Office, Gov. Phil Murphy signs legislation to raise New Jersey's minimum wage to $15 per hour, Mon., Feb. 4, 2019, in Elizabeth, N.J. Edwin J. Torres/N.J. Governor's Office

New Jersey joins California, Massachusetts, New York and the District of Columbia in phasing in the higher rate. The $15 wage is a prominent policy goal of left-leaning groups, as well as the fulfillment of a key campaign promise by Murphy.

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The governor, Senate President Steve Sweeney and Assembly Speaker Craig Coughlin announced a deal on the higher wage last month following yearslong efforts by left-leaning groups and unions in the state to raise the wage.

Today, we made history. Today, we put New Jersey’s minimum wage on a path to $15/hour.

https://t.co/Pehn0g0O1y pic.twitter.com/iFEpUjsYhI — Governor Phil Murphy (@GovMurphy) February 4, 2019

Republican Gov. Chris Christie vetoed a similar bill in 2016 to raise the wage.

Republicans and many businesses testified during hearings the higher wage will increase costs and hurt commerce. On Monday, Republican senators raised concerns it would lead to businesses laying off workers and moving to automation.

Others worried if a recession hits, the high wage could be untenable for businesses.

"The amount of job loss that we are going to see among small businesses will be tragic," state Sen. Declan O'Scanlon said in a statement.

In an interview, Murphy, the former Obama administration ambassador to Germany, dismissed concerns over automation and said he hasn't seen evidence a higher minimum wage correlates to jobs lost because of artificial intelligence or automation.

He also acknowledged raising the minimum wage too high too fast could hurt the state's economy, which is why the measure phases it in, he said.

"I start from the basis that you've got full-time work earning poverty wages in 2019 in New Jersey," he said. "There's no excuse that could justify this."

The bill raises the current $8.85 minimum wage to $10 an hour in July, and then increases the rate by $1 in subsequent years until it reaches $15 in 2024 — but not for all workers.

Farm workers' wages will climb to $12.50 over five years, for example. Workers for small businesses and seasonal employees will see their minimum wage reach $15 an hour only in 2026. Tipped workers, who currently have a minimum hourly wage of $2.13, will see it climb to $5.13 an hour by 2024.

The new law comes as the 2020 presidential contest begins to take shape, with Sen. Cory Booker of New Jersey announcing last week his plan to compete in the Democratic primary next year.

Oliver, the lieutenant governor, implored those assembled Monday to push for a higher minimum wage as part of the next election, eliciting one of the loudest applauses of the day.

"I don't want you to forget 2020 because we need a federal minimum wage (increase)," she said.

A constitutional amendment that raised the minimum wage and requires it to climb with inflation went into effect in 2013 in New Jersey. Once the wage reaches $15 in 2024, it will continue to climb based on the consumer price index because of that amendment.