Plenty of people, including me, think Dodd-Frank's implementation is taking too long.

The sooner the rules are on the books, the sooner we'll know what's working and be able to fix what's not. This camp believes bringing Dodd-Frank to life is an important step toward restoring the public's trust in the banking business.

HSBC Chief Irene Dorner was the most recent CEO to make this case.

"Quite simply, it's all taking too long to implement," Dorner said of financial reform at American Banker's annual regulatory symposium last week. The delay feeds uncertainty and hesitancy, she said, and that is harming economic growth.

(To see more posts from Barb Rehm's Blog, click here.)

Treasury Secretary Jack Lew has made getting Dodd-Frank done a priority. "[T]here is a growing understanding that once the rules are in place, there will be time to see what is working and what is not, and then we can make appropriate adjustments," he said in July.

In June, I wrote a column warning bankers and regulators that the slow-walk could produce a backlash in Congress, which could enact an even harsher law.

I still believe that, but enough smart people have told me I'm wrong that I wanted to present the counter-argument.

First, federal rules, once written, are rarely changed.

"Once you get a rule out, the willingness to revisit it is virtually zero," says one regulation-writer-turned-banker. "Nothing ever gets fixed after the fact."

Second, no rule is better than a lousy one.

"Living with a bad outcome is worse than living with no outcome," is how this source put it.

And finally, even without the formal rules in place, Dodd-Frank's mandates are being applied, especially to the largest banks.

"The real action is what they are doing to us" behind the scenes, "which dwarfs all the rule-writing," another bank executive says.

Getting regulatory approvals on models for capital and liquidity calculations is difficult, he says, and pressure to reduce risk is forcing banks to leave certain businesses and to drop various clients.

"They are putting everyone out of the capital markets business," this banker said.

This idea that regulation is broader than just the rules on the books is an important and easy-to-overlook factor here.

Supervision is comprehensive and cumulative and it comes at institutions from a number of angles.

Let's take capital rules for example.

First there's the actual compliance with various capital rules, including the ones from the Basel Committee. Dodd-Frank layers on the Collins amendment, which sets a floor under capital levels.

Then there are stress tests to ensure the largest banks have enough capital to withstand economic shocks. Then there are several capital surcharges for the biggest banks.

And of course there are individual safety and soundness exams where regulators have authority to require however much capital they think is necessary.

So like most policy questions, there are two sides to this one. Yes, five years on we should have more than 40% of Dodd-Frank implemented. A more complete process would bring clarity to the business and would help convince the public that the government has a grip on the risks posed by financial system.

But it's also true that we need effective rules because do-overs are unlikely. (That's a shame, but also a reality.) And Dodd-Frank has many belts and more than a few suspenders so even without full implementation, regulators have a lot of tools to tame risk-taking.

Bill Isaac, the former FDIC chairman who's now chairman of Fifth Third Bancorp (FITB), was one of the people who disagreed with that column I wrote in June. So I thought I'd give him the last word. Isaac was traveling on Monday, so he weighed in by email.

"What a Hobson's choice!" Isaac wrote.

"Quickly slap together regulations implementing a very bad law that is punitive, ineffective, and worse yet counter-cyclical in order to provide greater certainty about the rules of the road or be more deliberate in order to limit the damage at the cost of increasing uncertainty. I vote for more deliberation in the hope that sanity will prevail before too much more damage is inflicted on the banking system and the economy."