Democrat Ron Barber, a staffer for ex-Rep. Gabrielle Giffords, won the highly competitive Arizona special election to succeed his former boss Tuesday.

Barber defeated Republican Jesse Kelly, 53 percent to 45 percent, according to the Associated Press. Giffords, a Democrat, resigned in January in order to focus on her rehabilitation after an assassination attempt in January 2011. Barber was also seriously wounded in the shootings.

The victory means more than saving a single House seat for Democrats. On a personal level, it means Giffords’ chosen candidate will succeed her in Congress. On a national level, it gives Democrats some much-needed good news.

Both parties invested heavily in winning the special election. The parties’ House campaign arms along with their allied outside groups spent more than $2 million combined on the race — not counting what the candidates spent.

Democrats will likely point to TV advertising and rhetoric criticizing Kelly over Social Security and Medicare as one of the keys that helped ensure Barber’s victory. That was the plan from the start, and it was executed up until the final hours of the race. The ads worked. Elderly people in Tucson associated Kelly with entitlement cuts and voiced fears over the idea of his election to Congress.

But the election was about much more than those issues. Giffords campaigned for Barber over the weekend and excited the Democratic base in the campaign’s final days. Still, strategists will likely point to their early voting strategy as the biggest factor in Barber’s win. More than half of the votes in the special were cast before Tuesday.

Barber now gets to run for re-election this fall in a renumbered district that is slightly more favorable for Democrats. Kelly has said he will run again, but he faces an Aug. 28 primary and uncertainty about whether the national party will get behind him as its standard-bearer for a third consecutive time.