How would the presidential candidates get along with Congress? What are the prospects for success in a serious policy agenda in 2009? I have addressed these questions before in a rudimentary fashion. But as we get closer to a Democratic nomination (how close we don’t know yet) and as the candidates refine their policy positions, these queries become more relevant and deserve a lot of analysis, reflection and scrutiny.

[IMGCAP(1)]Let’s start with the shape of the Congress to come. The odds are very strong — close to overwhelming — that Democrats will add to their margins in both chambers of Congress. In the House, a gain of five to 15 seats seems like a reasonable range; in the Senate, a gain of three to seven seats is in the ballpark. Thus, the next Congress could have around 245 or so Democrats in the House and 56 or so in the Senate.

For a putative President Hillary Rodham Clinton or Barack Obama, those numbers sound very encouraging — until they realize that Bill Clinton entered the White House with more than 250 Democrats in the House and 58 Democrats in the Senate, but had an utterly miserable first two years. We know what happened: Republicans, after 12 years in the presidential saddle but a near-perpetual minority status in Congress, basically told Clinton that he and his party were on their own. Any serious policy accomplishments would have to be done with Democratic votes and no GOP support.

Despite the comfortable Democratic majorities in both houses, that proved nearly impossible. Clinton’s hope of hitting the ground running died when Republicans refused to provide a single vote in either chamber for his top-priority economic recovery plan, and Democrats would not unite to give him a quick victory that would have been a springboard to further policy successes.

It took him seven months to get majorities by single votes in the House and Senate, each requiring humiliating pandering, much of it in public, by the White House. At least the president got his economic plan — which, by the way, proved to be a very effective jump-start for the economy. In his second year, Clinton saw his (and his wife’s) signature health care plan go down in flames via a combination of GOP intransigence and Democratic disunity, not helped by a series of tactical miscues by the Clinton team.

What would be different 16 years later in 2009? Democrats might be more disciplined and less resistant to presidential initiatives. In 1993, nearly all House Democrats had spent their entire careers in the majority. They had seen presidents of both parties come and go, with little impact on their own re-elections. They simply did not see the president’s success or failure as linked in any fashion to their own futures.

In 2009, the vast majority of Democrats in Congress will have spent a large share of their careers in the minority. They know what happened to their colleagues in 1994 when the disarray in their party resulted in a huge GOP victory and the loss of their majority. So the lure to hang together to avoid hanging separately will be much greater. But these are still Democrats; the likelihood of the kind of discipline House Republicans showed for President Bush in his first two years is slim.

As for Republicans, the task for a Democratic president in 2009 would be more daunting. In 1994, although on big issues like the budget Republicans all united against the president, Clinton did find GOP votes for many other policies, mostly among the fairly robust group of moderates in both houses. Most of those are gone, and the remaining core of moderates, along with the conservatives whose instinct is to find bipartisan solutions to problems, is going to be down to a trace element next year. At the same time, the Senate has changed, in one fashion in particular. In 1993-94, the filibuster was not a routine tool of obstruction by the minority; it was used and threatened sparingly. In 2009, it will likely be applied as it has been in 2008 — regularly and indiscriminately, to slow down the process even when there is a broad consensus.

For Obama, the biggest challenge as president would come from those to his left — their sky-high expectations that big and transformational policy change is coming will be shattered because his road to early policy success will come from compromises with Republicans, and conservative ones at that. For Hillary Rodham Clinton, the challenge will be finding a new path to success in health policy. She has made it clear that she won’t put together a plan in secret and won’t make it thousands of pages of details that virtually preclude amendment. But if she insists from the get-go on universal coverage, it may give Republicans all the traction they need to resist going along — “We wanted to work with her, but here is another government-run health plan.”

What about a John McCain presidency? Ronald Reagan showed that a Republican president can find success in divided government. To do so, though, requires not only a president willing and able to cut deals with the other party, but retaining key support from within his own ranks. Republicans in Congress believed Reagan when he said he would hold firm and not compromise — and when he did, they believed he had to, and only after he had achieved the best deal possible.

For McCain, the challenge will come from his right, from conservatives who believe that he is more comfortable dealing with the opposition than with his own, that he will cut a deal with Sen. Edward Kennedy (D- Mass.) before he consults with Sen. Mitch McConnell (R-Ky.). And the Democrats in 2009 will be much more liberal than were the Democrats who were in the House in 1981, making conservatives even more suspicious of presidential deal-making with the Congressional majority.

It is of course possible that conditions in the country will create opportunities for major policy movement that comes with a sweeping election change. But the conditions will also make sustained policy success difficult no matter who gets elected president. We need to probe the candidates to see how well they understand the challenges they have ahead in Washington, and how prepared they are to overcome them.

Norman Ornstein is a resident scholar at the American Enterprise Institute.