HEREFORD, Ariz.  No migrant would have dared cross from Mexico into this particular stretch of Arizona on Sunday.

Hundreds of Tea Party activists converged on the border fence here in what is typically a desolate area popular with traffickers to rally for conservative political candidates and to denounce what they called lax federal enforcement of immigration laws. The rally brought a significant law enforcement presence as well as numerous private patrols by advocates of a more secure border.

But rallies, even daylong ones, are no way to seal the border. The Obama administration insists that its statistics show that significant financing increases in the federal Border Patrol have helped bring down crime at the border and make the smuggling of immigrants and drugs harder than ever.

But the activists who gathered Sunday had a decidedly different take. The border, in their view, is still far too easy to get across and has become so dangerous that some of them brought their sidearms for protection. Organizers urged participants to leave rifles in their cars.