Without a doubt, many residents of Pennsylvania’s 9th Congressional District were taken aback Tuesday by the news of Republican U.S. Rep. Bill Shuster’s retirement at the end of his current term.

The unexpected news means that, at the beginning of next year, the 9th District apparently won’t be represented by a congressman bearing the last name “Shuster” for the first time since 1973.

Bill Shuster’s father, former longtime congressman Bud Shuster, represented the district from 1973 until his retirement in 2001. Bill Shuster succeeded his father by winning a special election that year and has won re-election every two years since he was elected to his first full term in 2002.

The congressman’s decision can be expected to produce more than a couple of contenders for the House seat in the weeks ahead, as candidates of both the Republican and Democratic parties line up for what no doubt will be spirited campaigns. It would not be a surprise if several hopefuls emerged from Blair County.

Beyond that, there no doubt will be aggressive campaigns waged by the Democratic and Republican nominees once the primary elections are over.

That is as it should be, especially at this juncture when the nation’s political scene is so polarized.

Many political observers near and far will be interested in following whether the GOP will be able to maintain its stranglehold on the 9th District, considering President Donald Trump’s consistently low poll numbers during much of the past year.

Many Republicans were successful in November 2016, riding Trump’s coattails at a time when his popularity was soaring at its greatest heights.

With the president’s popularity having taken a nosedive, the uncertainties tied to the ongoing Russia investigation, the lack of an incumbent vying for re-election and the oftentimes occurrence of Congress’ minority party making significant inroads during a midterm election, if there’s ever a time when the district might be regarded as a toss-up, 2018 might be that year.

The news about Bill Shuster, which first was reported in the Washington Examiner and confirmed shortly thereafter by the Mirror, made clear that the congressman — commendably — doesn’t intend to spend a leisurely last year in Washington.

Shuster, chairman of the powerful House Transportation Committee, said he wants to spend his final year in Congress working closely with Trump on a large, national infrastructure-upgrade initiative without the distraction of campaigning.

If Shuster is successful in helping the president achieve that goal, it would represent a Shuster accomplishment like so many that his father produced for Pennsylvania and other states.

Still, one of his biggest disappointments on the national landscape might be his failure to bring about privatization of the air-traffic-control system, although that goal cannot yet be deemed officially dead.

As part of his retirement announcement, the congressman rightly observed that the infrastructure initiative is “much needed to rebuild America,” and there are a number of potential projects in central Pennsylvania worthy of the infrastructure measure’s funding.

Shuster will be missed, and it’s to be hoped that his eventual successor will be as effective — as good of a leader — as he has been.