Whenever an incumbent president struggling in the polls makes a visit to a battleground state, downballot candidates are faced with the choice of whether to make a joint appearance – and face the consequences – or to, coincidentally, have other plans.

President Obama and former Virginia governor Tim Kaine (D). (Linda Davidson/The Washington Post)

Sen. Sherrod Brown (D-Ohio), who is running for a second term, joined Obama for his first event of the day at Ohio State University in Columbus. Brown is facing state Treasurer Josh Mandel (R) in a race that the Cook Political Report rates as “Lean Democratic.”

And in Virginia, former governor and Democratic National Committee chairman Tim Kaine appeared onstage at Obama’s rally at Virginia Commonwealth University. Kaine is locked in a tight battle against former senator George Allen (R) in what’s expected to be the most competitive of nine Senate races this year ranked as toss-ups.

Obama won both Ohio and Virginia four years ago, but looks to face a tougher time this year. His approval rating is at 48 percent in Ohio and, while he is faring better at 53 percent in Virginia, those numbers are likely to shift as the campaign progresses.

One factor working in Obama’s favor in both states – the unemployment rate is below the national average. Ohio’s unemployment rate was 7.5 percent in March, while Virginia’s was 5.6 percent, both below the national average of 8.4 percent.

Kaine, who was one of the earliest supporters of Obama’s 2008 presidential bid, in recent months has embraced Obama in his campaign-trail appearances. But he has also openly criticized the president, particularly over the White House’s move earlier this year to require some religious institutions to cover the cost of employees’ birth control.

Brown, too, has walked a fine line when it comes to his relationship with Obama. Earlier this year, Brown was not on hand for an Obama economic speech in the Cleveland area. And he has parted ways with Obama on some policy issues, including a high-profile China currency bill that Brown has spearheaded but on which the White House has declined to state its position.

But both Brown’s and Kaine’s appearances with Obama on Saturday would suggest that both Democrats view the president as more of an asset than a liability.

It will be worth watching whether their approach changes as the campaign heats up over the coming weeks and months.