When is right time to replace Eric Holder? Depends which party you ask.

Republicans, who believe they may take the Senate, say they want to wait until 2015 to replace the attorney general. Democrats disagree. Lawmakers are also divided on when to debate broader authorization for war against Islamic State.

Uncertain about the outcome of the midterm elections, members of Congress are at odds about whether to take up two hot topics in the coming lame-duck session: authorizing use of force against the Islamic State and confirming a replacement for outgoing Attorney General Eric Holder.

House Speaker John Boehner told The New York Times on Thursday that the House should wait until the new Congress is seated to debate authorization for use of military force against the Islamic State (IS), rather than doing that in the lame-duck session, as some members from both parties are urging. 

“Doing this with a whole group of members who are on their way out the door, I don’t think that is the right way to handle this,” Speaker Boehner said. “I would suggest to you that early next year, assuming that we continue in this effort, there may be that discussion and there may be that request from the president.”

The issue of timing for a replacement for Mr. Holder, who announced his resignation on Thursday, splits along party lines.

Sen. Chuck Grassley (R) of Iowa, who would be in line to chair the Senate Judiciary Committee if Republicans win control of the Senate Nov. 4, warned against rushing a nominee through a lame duck session. Sen. Patrick Leahy (D) of Vermont, the current chair, wants confirmation hearings “as quickly as possible.”

It’s hard to predict how much business the lame duck session will take up. 

“We’ve had both very unproductive and productive lame ducks,” says Senate historian Donald Ritchie. “Sometimes it depends on how much change the election has brought.” 

After the elections, the parties will look at the results and weigh whether they “can do better or not in the next Congress” or whether they want to “take on the burden of a particular issue.”

Suppose the election brings GOP gains to the Republican-controlled House and flips the Senate to GOP control – as some observers predict. In the case of a replacement for the controversial Holder, President Obama would have an easier time of confirmation in a lame duck Senate still controlled by Democrats. 

If he waited until next year, he would need to find an attorney general with broader appeal.

That’s certainly what Senator Grassley is hoping for.

“Rather than rush a nominee through the Senate in a lame-duck session, I hope the president will now take his time to nominate a qualified individual who can start fresh relationships with Congress so that we can solve the problems facing our country,” he said Thursday.

As for war authorization, that issue may blow up on Boehner when Congress returns on Nov. 12 to take up unfinished business. 

Lawmakers have two main tasks before them when they reassemble.

One is to fund the federal government and the other is to authorize training and arming of Syrian rebels. Temporary provisions for both run out on Dec. 11. Both also contain the seeds of debate for broader war authorization because they relate to military spending and Syria. 

Senate leadership, meanwhile, has said it will begin debate on authorization for a broader military campaign in the lame-duck session. The obvious start this week of a new and years-long phase in the war on terrorism also carries with it its own urgency.