The Democratic Party is being transformed. These House votes show how.

U.S. House Speaker Nancy Pelosi (D-CA)  swears in members of the 116th Congress on Capitol Hill, January 3, 2019.

(CNN)The decisive House of Representatives vote last Friday barring discrimination based on sexual orientation or gender identity marked a milestone in shifting American attitudes toward gay rights. But it also represented a landmark in the evolution of the Democratic Party into an urbanized coalition centered on the voters and communities most comfortable with social and demographic change.

In last week's vote, not a single House Democrat opposed the "Equality Act," which would outlaw discrimination in employment, housing and public accommodations for gay and transgender Americans. That extended a pattern of virtual unanimity among House Democrats this year on social issues, including gun control and immigration, that earlier divided the party between its members from metropolitan and rural districts.
That convergence among House Democrats has been almost completely overshadowed by the debate over whether to pursue impeachment against President Donald Trump, and the confrontations ignited by his efforts to block congressional oversight of his administration. But the repeated unanimous, or nearly unanimous, House votes this year for key items on the party's agenda underscore how its increasing dominance of urban and suburban seats, and its diminishing reliance on culturally conservative rural districts, is allowing Democrats to minimize the divisions that plagued their earlier House majorities, particularly on social issues.
"The generalization has been that when we have a hefty majority we have a lot of people from (swing) districts that make it hard to maintain our unity," said David Price, a longtime Democratic representative from North Carolina and former political scientist. "That's what has changed. We still have some challenges, and they may take a somewhat different form, but these traditional divisions just aren't what they used to be, not even close."
    This unity is not without risk for Democrats: The convergence behind a uniformly liberal agenda on social issues could limit the party's ability to regain ground in small-town and rural areas that have steadily trended toward the GOP over the past decade, not only in congressional but also presidential elections. But it also means the party can now advance the agenda of its predominantly urban and suburban coalition on issues such as gay rights and women's rights, gun control and immigration far more smoothly than when Democrats from such non-urban areas consistently resisted bold action on those fronts.
    "What used to be unthinkable to people is not anymore," says Democratic Rep. Zoe Lofgren, who represents a district centered on California's Silicon Valley.
    While the Republican-controlled Senate has shown no willingness to consider any of the major legislation from House Democrats, the party is steadily accumulating votes that will allow its members to argue in 2020 that they upheld the priorities they ran on in 2018. And for a party accustomed to squabbling, House Democrats have reached a striking, if largely unnoticed, degree of unity on those issues.

    Early bills get consensus votes

    After winning the majority, House Democrats said they would mark their priorities by labeling a slate of bills as HR-1 through HR-10. So far the party has identified nine of those priorities (it hasn't yet disclosed what issue HR-10 will address).
    Of those nine bills, five have already reached floor votes. Four of those passed without a single dissenting vote among Democrats: legislation to sweepingly overhaul voting and campaign finance laws (HR 1), promote equal pay for women (HR 7), support America's reentry into the Paris accord to combat global climate change (HR 9) and the Equality Act (HR 5). Legislation to impose universal background checks for gun purchases (HR 8) passed with support from 232 House Democrats and just two who voted no.
    Key bills outside of this priority list have achieved comparable levels of consensus. Only one House Democrat voted against April legislation to reauthorize the Violence Against Women Act, and only one voted in March to support Trump's assertion of emergency authority to finance building his border wall. None opposed legislation in April to restore federal "net neutrality" rules for the internet, or legislation in May to overturn Trump regulations allowing states to loosen the Affordable Care Act's protections for patients with preexisting conditions. A bill to lengthen the time allowed for background checks on gun purchases generated a slightly wider split in February, but even that drew support from 225 House Democrats and opposition from just seven.
    House Democrats, of course, haven't completely eliminated their disagreements. Earlier this year, party leaders were embarrassed when defections from a block of Democrats allowed Republicans to pass two "motions to recommit," a procedural tool that allows the minority party to influence legislation. Splits between moderate and more liberal members have also delayed the party's plan to approve a nationwide $15 minimum wage, though leadership aides insist internal negotiations will eventually produce a final agreement. Most visibly, the push from the party's energized liberal vanguard for a sweeping "Green New Deal" and a single-payer "Medicare for All" system that would eliminate private health insurance have stalled out, with fewer than half of House Democrats, and virtually no members from swing seats that voted for Trump in 2016, cosponsoring each plan.
    But overall, Democrats are coalescing around their top priorities far more than in earlier periods when they controlled the House. During Bill Clinton's presidency, 41 House Democrats voted against his initial budget plan -- the cornerstone of his domestic agenda -- and his universal health care blueprint faced so much resistance that it never came to a vote in the chamber. In 1993, 69 House Democrats voted against the Brady bill to establish the background check system for gun purchases; the next year, 77 House Democrats opposed the assault weapon ban. And in 1996, 118 House Democrats voted for the Republican-crafted "Defense of Marriage Act," which allowed states to refuse to recognize same-sex marriages performed in other states and barred the federal government from recognizing such unions.
    Only 65 House Democrats voted against that bill, almost exactly half of them from just New York and California; Democrats from the other states supported by the bill by more than 3 to 1. Lofgren was among the minority who opposed the bill. In an interview after last week's vote, she said the decisive shift toward unified Democratic support for the Equality Act reflected changes in both the country and the party.
    "It's such a sea change from the DOMA bill, and I think the divisiveness between Democrats is very low," she said. "The press, sometimes because it's boring to say people agree, believes the interesting story is disagreement. But the Democratic caucus is very cohesive."

    Vanishing 'blue dogs'

    Compared with the Clinton era, the party was only slightly more unified when it last held the House majority in 2009 and 2010, the first two years of Barack Obama's presidency. Thirty-four House Democrats opposed final passage of the Affordable Care Act in 2010, and 44 of them voted in 2009 against cap and trade legislation to reduce the carbon emissions associated with global climate change. So many House Democrats opposed comprehensive immigration revisions and gun control that neither idea ever reached a floor vote over those two years.
    The party's most consistent fault line over all those years ran between generally more liberal members from urban and suburban districts and more moderate to conservative "blue dogs" -- such as then-longtime members John Spratt of South Carolina, John Murtha of Pennsylvania and Ike Skelton of Missouri -- representing small-town, exurban and rural district with large concentrations of working-class white voters. As late as the 2009-2010 Congress, the last time Nancy Pelosi held the speaker's gavel, about