Presidential candidates have the opportunity to set the national agenda by bringing forward new proposals and innovative policies.

Some do this: Bill Clinton in 1992, George Bush in 2000. Others don’t. Like most or all of the 2008 candidates.

Click through their Web sites, and what you find is pretty thin gruel. Especially so from the two leading in the polls. Hillary Clinton’s home page links to her recent Senate speech on Iran, but not her 2002 speech backing the Iraq war resolution. She calls for putting “some of the oil industry’s windfall profits into a fund that would help develop practical new sources of renewable energy,” but with no details. You might find out more by clicking on her “Let the Conversation Begin” Webcasts.

Rudy Giuliani tells you even less. His exploratory committee Web site has an account of his work as mayor of New York. But I could find nothing on what he would do as president. John McCain’s Web site makes some interesting points. As president, he would “use the veto pen” on pork and earmarks.

The section on “human dignity and the sanctity of life” mentions his opposition to abortion for many years and to funding embryonic stem cell research: a reminder to cultural conservatives that he’s been on their side, though he has seldom talked about it. For Iraq, he wants a “more robust counterinsurgency strategy” — which seems to be underway now.

Barack Obama’s issue positions seem to be taken more or less intact from his senatorial Web site. He cites his work with various Republican senators on important issues. He wants government to assume domestic autoworkers’ health care costs if they invest half in fuel-efficient technology, and he promises more “resources” to teachers: something for the United Auto Workers and the teachers unions.

John Edwards provides more detail. He wants withdrawal from Iraq “within 12-18 months,” plus direct talks with Iran and Syria, and a regional peace conference. Would Israel be invited? Variety reported (and Mr. Edwards denied) that he told a Hollywood crowd an attack by Israel on Iran was the greatest threat to world peace. He calls for universal health insurance through requiring employer coverage, expanding Medicaid, “reform(ing) insurance” and restricting drug ads. Eliminating poverty, his trademark theme in 2004, gets one paragraph.

Mitt Romney has an Issue Watch tab, with single-paragraph discussions of eight issues and multiple recent Romney quotes. He calls for “address(ing) entitlement programs” and universal health insurance “through market reforms.”

Single-digit candidates’ Web sites vary.

Mike Huckabee has a four-word slogan and a YouTube link. Duncan Hunter discusses border security, trade, and the war on terrorism. Joe Biden has a few paragraphs on 10 issues (with Afghanistan and Darfur treated as one issue). Chris Dodd identifies six issues but has single paragraphs on only four so far. Jim Gilmore reports on his record as governor of Virginia. John Cox, a Chicago-area accountant who ran for the Senate in 2004, wants lower spending, calls global warming “overblown,” and stresses his opposition to abortion.

Some offer more. Bill Richardson invites you to sign a petition for diplomacy with Iran and has one-paragraph takes on seven issues. Dennis Kucinich’s front page is mostly about Iraq but has links to long comments on 10 issues, from health care to the Patriot Act. Mike Gravel highlights his opposition to the Iraq war and his proposals for national initiative elections. Sam Brownback mentions issues he’s taken the lead on (human rights, Darfur) and calls for a $5,000 tax credit for rural first-time homebuyers. Tom Tancredo starts with immigration, his signature issue, but provides some detail on 10 others (he’s for a flat tax or national sales tax).

Yes, it’s early yet. The candidates haven’t had time to get issue shops up and running. Presidents Clinton and Bush got started much later in the 1992 and 2000 cycles. But so far, candidates have told us very little about where they think the world is headed and what we should do about it. And they’ve shown us little to indicate that they’ve thought seriously about governance and long-term problems like Social Security and Medicare.

Let’s hope they do better as they make their way through Iowa’s 99 counties and New Hampshire’s 234 cities and towns.